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投資，是放大人性的機率遊戲：善用數理邏輯解鎖投資心理戰，超人氣數學家用血淚悟出的市場硬道理
數學，是人類丈量股市的工具，但股市，卻是考驗人性的修羅場──你的投資邏輯，是事實、感受還是信仰？記住：市場的錢賺不完，但你口袋的錢卻賠得完。投資要成功，不只是與數字、公式打交道，更要了解人性如何與市場互動，才能避免投資血本無歸！ ★一位瘋股票的數學大師的慘賠自白──參透股市人性、避開投資錯誤，最具價值的參考著作 ★《金融時報》《紐約時報》《USA Today》《華盛頓郵報》《華爾街日報》──五大重量級媒體一致背書！ ★知名財經作家──綠角〈專文推薦〉 ★Jet Lee（「Jet Lee的投資隨筆」版主）、遠得要命的數學王國（經濟學科普部落客）──好評推薦 一位舉世聞名的數學家， 買進一檔氣勢如虹的股票之後， 領悟出：股市，如何遵循和扭曲人性與數學原理！ 從選股策略、交易心理到量化風險， Step by Step，解答投資難題的9堂驚奇數感課 記住：要愛人、愛自己與生活， 但是，不要愛上股票── 投資者如何落入錨定效應，「苦等股價漲回前高」？ 用均線能掌握趨勢，還是技術分析派只能當線仙？ 複利、折現……如何看懂金錢的時間價值？ 錯誤的報酬率如何
202 pages, Kindle Edition
First published January 1, 2003
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January 21, 2013
Somewhat entertaining, but about half the book is anecdotes that have been published many many times by many others.
That leaves about 101 pages that are original.
I think he makes a number of mistakes in trying to understand the stock market.
P64 He compares stock prices to flipping a coin,
a coin has no memory or emotion,
stock prices behave very differently.
p127 He says Fed regulations require that the amount you owe your broker be no more than 50% of total market value of your holdings.
Not true, the day you borrow the money, the most you can borrow
is 50%, but if your stocks go down you don't get a margin call
until your equity is 30-35% of total value,
and the margin call doesn't require you to get back to 50%,
usually it's 40%.
Different stock brokers have slightly different rules,
but none are like what he describes.
He interjects standard deviation a number of times.
SD and the bell curve work great with human attributes
like IQ and height,
But not with stock returns.
Plotting stock returns, the tails are much fatter than the
usual bell curve, and there are a lot more data points near
the mean.
p157 he says risk is volatility,
ridiculous,
High volatility is my friend,
it allows me to buy low and sell high much more often than
when volatility is low.
Risk is too much debt, or stock options that lead management to go for double or nothing strategies.
Or your broker changing policies and demanding that you comply now or they will take action without your permission.
Also political meddling, nationalization, changes in tax laws,
government policies that favor the mania of the day like
what surrounds the current debate about greenhouse gases and whether recent warming is the result of burning carbon fuels or natural fluctuation that has gone on for millions of years.
Did humans cause the ice ages?
Of course not, but no one knows what the cause was,
just that the earths temperature has always fluctuated.
A lot, and frequently.
p 158 he says investors can always borrow at the risk-free interest rate.
I don't know what he means by this,
but I know I can't borrow from any one at the same rate the US Treasury can.
That's what most people think of when talking about risk-free interest.
p 183 he rants about drug companies not looking for drugs that'll cure
poor people in poor countries.
Gee, does it have anything to do with the fact these countries don't respect patents or contribute anything to research?
He also rants about the richest 1% owning 50% of all stocks.
So Warren Buffett is worth about $50 Billion,
so what?
He has lived in the same modest house for more than 50 years,
drives an old car,
and thinks a hamburger and fries is a great dinner.
He has created over $200 Billion dollars of wealth for himself
and others and spends almost none of it on himself.
And when he dies his wealth wont' disappear.
Personally I divide people into 2 categories,
1. those that produce more than they consume,
2. and those that consume more than they produce.
People in cat 1 make the world richer for all of us.
People in cat 2 are parasites.
That includes trophy wives that spend ungodly amounts of money
on clothes and other junk.
And also welfare queens who may be poor, but produce nothing,
only draining wealth away from people who do work.
Jackie O often spent $400,000 dollars in today's money shopping
yet never did any real work.
That leaves about 101 pages that are original.
I think he makes a number of mistakes in trying to understand the stock market.
P64 He compares stock prices to flipping a coin,
a coin has no memory or emotion,
stock prices behave very differently.
p127 He says Fed regulations require that the amount you owe your broker be no more than 50% of total market value of your holdings.
Not true, the day you borrow the money, the most you can borrow
is 50%, but if your stocks go down you don't get a margin call
until your equity is 30-35% of total value,
and the margin call doesn't require you to get back to 50%,
usually it's 40%.
Different stock brokers have slightly different rules,
but none are like what he describes.
He interjects standard deviation a number of times.
SD and the bell curve work great with human attributes
like IQ and height,
But not with stock returns.
Plotting stock returns, the tails are much fatter than the
usual bell curve, and there are a lot more data points near
the mean.
p157 he says risk is volatility,
ridiculous,
High volatility is my friend,
it allows me to buy low and sell high much more often than
when volatility is low.
Risk is too much debt, or stock options that lead management to go for double or nothing strategies.
Or your broker changing policies and demanding that you comply now or they will take action without your permission.
Also political meddling, nationalization, changes in tax laws,
government policies that favor the mania of the day like
what surrounds the current debate about greenhouse gases and whether recent warming is the result of burning carbon fuels or natural fluctuation that has gone on for millions of years.
Did humans cause the ice ages?
Of course not, but no one knows what the cause was,
just that the earths temperature has always fluctuated.
A lot, and frequently.
p 158 he says investors can always borrow at the risk-free interest rate.
I don't know what he means by this,
but I know I can't borrow from any one at the same rate the US Treasury can.
That's what most people think of when talking about risk-free interest.
p 183 he rants about drug companies not looking for drugs that'll cure
poor people in poor countries.
Gee, does it have anything to do with the fact these countries don't respect patents or contribute anything to research?
He also rants about the richest 1% owning 50% of all stocks.
So Warren Buffett is worth about $50 Billion,
so what?
He has lived in the same modest house for more than 50 years,
drives an old car,
and thinks a hamburger and fries is a great dinner.
He has created over $200 Billion dollars of wealth for himself
and others and spends almost none of it on himself.
And when he dies his wealth wont' disappear.
Personally I divide people into 2 categories,
1. those that produce more than they consume,
2. and those that consume more than they produce.
People in cat 1 make the world richer for all of us.
People in cat 2 are parasites.
That includes trophy wives that spend ungodly amounts of money
on clothes and other junk.
And also welfare queens who may be poor, but produce nothing,
only draining wealth away from people who do work.
Jackie O often spent $400,000 dollars in today's money shopping
yet never did any real work.
September 17, 2015
What's really interesting about other people's reviews of this book is that they seem to expect a book on the stock market from a mathematician to be somehow be based in finance.
There are plenty of books on the stock market out there... that do so from a finance point of view.
This book is pretty brilliant although at first glance, it appears to be pretty straight forward... you think a mathematician would use his knowledge about math to somehow find some brilliant trick about the stock market. But that's not how this plays out.
Math is a game of numbers. It's a field of study that looks at patterns. But ultimately the numbers are a measurement, some kind of metric. What's faulty about using the stock market from a pure numbers point of view is that the numbers in stock prices need to measure the a consistent value for any math relation to work. What I mean is simply that stock prices are based on what people do in terms of trading volume of a stock. Abstract all you like, but the immediate particular reason why anyone does what they do with stock is anyone's guess.
We can assume that a change in stock prices has to do with an anecdote on the news about a company, or something happening somewhere related to a company. But that's not always true. Sometimes things happen for seemingly no reason. Much of this, Paulos tries to explain has as much to do with how people perceive the market as much as it has to do with actual values. The later chapters are particularly brilliant on this account. The earlier chapters which seemed to promise this or that mathematical model, or this or that economic model... don't pan out because as Paulos convincingly tells us, any model that we use to predict the stock market can be outdated unless the model itself anticipates how others will use it, made predictions and how those predictions will affect the market. In other words, any stock market model needs to also be self reflexive in how it's applied -- not just when it's applied.
Paulo makes some pretty complex abstractions to do this; for instance, applying how the "Efficient Market Hypothesis" is either always correct (when people believe it to be wrong, thus playing the stock market off of information in the news, or about a company's state) or it is always incorrect (when other people believe the information on the news is invalid as the stock prices already reflect the current value of the stock)... that is to say that particular hypothesis doesn't work as it should because it takes for its model an absolute system of values based on how other people act. People don't do things as mechanisms do; people evaluate based off of what they believe others will do as well.
This twist of self reflexivity makes it particularly difficult to formulate any theory that is both consistent (non-contradictory) and complete... in essence, we need to formulate a model that can predict how its predictions are taken into account and then provide us with "a few steps ahead" so that profit can be captured. That would be a pretty sophisticated theory; and in fact be impossible because that theory could only work in the case of the one individual who has it. By definition the same theory could not with all the other individuals who also have it, otherwise there would be no profit!
So a quick conclusion is that the market can at times reflect real values, but often it doesn't because there's too much white noise as meanings, theories, trends and news all impact the same metric. So how can we make any consistent model on the stock market if all this information flies under the same metric as the very metric a stock price is supposed to represent?
This is all of course, extracted from the book. What I found really interesting, if one read between the lines from the get go, was that one can always take the meaning of a stock's movement anyway one likes. That is to say, we have an abundance of narratives that can fit the model of "what really happens". We simply pick the one we like the best, and go forth as if that were true. As Paulo points out, even through random chance a few individuals are bound to hit it big. And once people notice that, they will follow that person's movements, ensuring that they will always be right.
Thus, the modeling of stocks, properly considered, must also model how we think as well. But that's nothing new. Paulo is of course, writing this book as a lament of his own failed investments...and in the process of doing so, he's also somewhat justifying the bubble bursting was inevitable, a kind of normal market behavior. But he's correct; the uncertainty in the stock market is not just an uncertainty as to what the price means, but similarly that its certainty is also a reflection of what we all would also believe it to mean.
All in all, I found the book to be really entertaining and interesting. I would have liked a little more direction midway through the book... with each theory or direction Paulo brought up, he quickly shot it down at the end of the chapter. Of course, he was setting this bed of failed theories for the self reflexive analysises... but I didn't see it coming. So it felt much like wandering, and that's not a good way to treat your reader as it throws your reader out of the process of reading.
There are plenty of books on the stock market out there... that do so from a finance point of view.
This book is pretty brilliant although at first glance, it appears to be pretty straight forward... you think a mathematician would use his knowledge about math to somehow find some brilliant trick about the stock market. But that's not how this plays out.
Math is a game of numbers. It's a field of study that looks at patterns. But ultimately the numbers are a measurement, some kind of metric. What's faulty about using the stock market from a pure numbers point of view is that the numbers in stock prices need to measure the a consistent value for any math relation to work. What I mean is simply that stock prices are based on what people do in terms of trading volume of a stock. Abstract all you like, but the immediate particular reason why anyone does what they do with stock is anyone's guess.
We can assume that a change in stock prices has to do with an anecdote on the news about a company, or something happening somewhere related to a company. But that's not always true. Sometimes things happen for seemingly no reason. Much of this, Paulos tries to explain has as much to do with how people perceive the market as much as it has to do with actual values. The later chapters are particularly brilliant on this account. The earlier chapters which seemed to promise this or that mathematical model, or this or that economic model... don't pan out because as Paulos convincingly tells us, any model that we use to predict the stock market can be outdated unless the model itself anticipates how others will use it, made predictions and how those predictions will affect the market. In other words, any stock market model needs to also be self reflexive in how it's applied -- not just when it's applied.
Paulo makes some pretty complex abstractions to do this; for instance, applying how the "Efficient Market Hypothesis" is either always correct (when people believe it to be wrong, thus playing the stock market off of information in the news, or about a company's state) or it is always incorrect (when other people believe the information on the news is invalid as the stock prices already reflect the current value of the stock)... that is to say that particular hypothesis doesn't work as it should because it takes for its model an absolute system of values based on how other people act. People don't do things as mechanisms do; people evaluate based off of what they believe others will do as well.
This twist of self reflexivity makes it particularly difficult to formulate any theory that is both consistent (non-contradictory) and complete... in essence, we need to formulate a model that can predict how its predictions are taken into account and then provide us with "a few steps ahead" so that profit can be captured. That would be a pretty sophisticated theory; and in fact be impossible because that theory could only work in the case of the one individual who has it. By definition the same theory could not with all the other individuals who also have it, otherwise there would be no profit!
So a quick conclusion is that the market can at times reflect real values, but often it doesn't because there's too much white noise as meanings, theories, trends and news all impact the same metric. So how can we make any consistent model on the stock market if all this information flies under the same metric as the very metric a stock price is supposed to represent?
This is all of course, extracted from the book. What I found really interesting, if one read between the lines from the get go, was that one can always take the meaning of a stock's movement anyway one likes. That is to say, we have an abundance of narratives that can fit the model of "what really happens". We simply pick the one we like the best, and go forth as if that were true. As Paulo points out, even through random chance a few individuals are bound to hit it big. And once people notice that, they will follow that person's movements, ensuring that they will always be right.
Thus, the modeling of stocks, properly considered, must also model how we think as well. But that's nothing new. Paulo is of course, writing this book as a lament of his own failed investments...and in the process of doing so, he's also somewhat justifying the bubble bursting was inevitable, a kind of normal market behavior. But he's correct; the uncertainty in the stock market is not just an uncertainty as to what the price means, but similarly that its certainty is also a reflection of what we all would also believe it to mean.
All in all, I found the book to be really entertaining and interesting. I would have liked a little more direction midway through the book... with each theory or direction Paulo brought up, he quickly shot it down at the end of the chapter. Of course, he was setting this bed of failed theories for the self reflexive analysises... but I didn't see it coming. So it felt much like wandering, and that's not a good way to treat your reader as it throws your reader out of the process of reading.
March 30, 2022
Interesante, y ameno al principio... luego sigue interesante hasta el final, pero se va enrevesando y haciendo cada vez más técnico (a nivel económico-bursátil y matemático), haciendo más farragosa y menos amena su lectura.
Por otra parte, creo que su mensaje está claro ya desde sus primeras páginas, y en pocas palabras coincide con algo que siempre he pensado: si de verdad el análisis bursátil fuese realmente efectivo, los analistas se dedicarían a analizar e invertir para sí mismos y hacerse ricos, no trabajarían a sueldo para supuestamente enriquecer a los demás.
El resumen es que, por mucho análisis, estadística, teoría del caos, etc, que se aplique, el comportamiento bursátil es tan absolutamente caótico (y en ese caos intervienen, entre otros, la psicología de masas y sus interacciones) que al final hay poco que se pueda hacer para ganar en bolsa por encima de la media del mercado. Por supuesto, siempre habrá quien gane por encima, y quien pierda... y por pura probabilidad, alguno que gane mucho y muchas veces, y lo contrario. Pero en la media, se seguirá la media...
Hala, ya he resumido un libro complicado en dos párrafos :-)))
Por otra parte, creo que su mensaje está claro ya desde sus primeras páginas, y en pocas palabras coincide con algo que siempre he pensado: si de verdad el análisis bursátil fuese realmente efectivo, los analistas se dedicarían a analizar e invertir para sí mismos y hacerse ricos, no trabajarían a sueldo para supuestamente enriquecer a los demás.
El resumen es que, por mucho análisis, estadística, teoría del caos, etc, que se aplique, el comportamiento bursátil es tan absolutamente caótico (y en ese caos intervienen, entre otros, la psicología de masas y sus interacciones) que al final hay poco que se pueda hacer para ganar en bolsa por encima de la media del mercado. Por supuesto, siempre habrá quien gane por encima, y quien pierda... y por pura probabilidad, alguno que gane mucho y muchas veces, y lo contrario. Pero en la media, se seguirá la media...
Hala, ya he resumido un libro complicado en dos párrafos :-)))
January 15, 2012
Entertaining but not really enlightening
June 27, 2013
Wow. What a weird book.
Paulos seems to be writing a glorified journal, since the only suitable audience for this book are people exactly like Paulos before he began heavily investing in Worldcom. Who else would both like math enough to want read a book about it and have almost no knowledge of basic financial theory at the same time? The two worlds seem so closely related that it's hard to imagine someone that is interested in one field yet hasn't really learned much about the latter.
And the financial theory in the book is definitely basic. It's essentially the same material that any student would encounter during their very first introduction to finance class. We have summary statistics for assessing performance, portfolio optimization, future and present value, technical indicators, financial statement analysis, and a very simple introduction to options, which does little more than defining calls and puts. Paulos is kind enough to include the math behind these ideas, but his subjects are so broad that the treatment is inevitably very shallow.
In between these sections is a smattering of asides and observations, many of which have only the most tangential connection to each other or the ideas in the more concrete sections of the book. Of course, this includes a very detailed history of Paulos and his relationship to Worldcom. But beyond that, things start to get really bizarre. At more than a few points in the book, I had to ask myself how Paulos thought that this section was related to a mathematical understanding of the stock market. This is true of many of the political statements, some of his jokes and a lot of the leaps into material that he admits covering more thoroughly in other books. The longest section in the book is a film treatment about a mathematician that stretches the meaning of the word relevance to its breaking point.
Stripping away most of the filler, there is at least a handful of decent ideas, even if all of them are not particularly novel. The paradoxes of individual agents within the EMH is quite fun, especially since for the EMH to be valid, there has to be a lot of people who believes that the EMH is false. He also has some decent extensions of the prisoner's dilemma to the stock market, and he shows how just the interactions between competing agents is often enough to develop financial turbulence.
But that's it, and these few flashes of insight are not enough to justify the existence of this book. At times it feels like Paulos simply slapped all of this together to make up for his bad investment decisions. People interested in the subject will find much more valuable reads in the book's index (which includes Mandelbrot and Taleb), than in the actual book itself.
Paulos seems to be writing a glorified journal, since the only suitable audience for this book are people exactly like Paulos before he began heavily investing in Worldcom. Who else would both like math enough to want read a book about it and have almost no knowledge of basic financial theory at the same time? The two worlds seem so closely related that it's hard to imagine someone that is interested in one field yet hasn't really learned much about the latter.
And the financial theory in the book is definitely basic. It's essentially the same material that any student would encounter during their very first introduction to finance class. We have summary statistics for assessing performance, portfolio optimization, future and present value, technical indicators, financial statement analysis, and a very simple introduction to options, which does little more than defining calls and puts. Paulos is kind enough to include the math behind these ideas, but his subjects are so broad that the treatment is inevitably very shallow.
In between these sections is a smattering of asides and observations, many of which have only the most tangential connection to each other or the ideas in the more concrete sections of the book. Of course, this includes a very detailed history of Paulos and his relationship to Worldcom. But beyond that, things start to get really bizarre. At more than a few points in the book, I had to ask myself how Paulos thought that this section was related to a mathematical understanding of the stock market. This is true of many of the political statements, some of his jokes and a lot of the leaps into material that he admits covering more thoroughly in other books. The longest section in the book is a film treatment about a mathematician that stretches the meaning of the word relevance to its breaking point.
Stripping away most of the filler, there is at least a handful of decent ideas, even if all of them are not particularly novel. The paradoxes of individual agents within the EMH is quite fun, especially since for the EMH to be valid, there has to be a lot of people who believes that the EMH is false. He also has some decent extensions of the prisoner's dilemma to the stock market, and he shows how just the interactions between competing agents is often enough to develop financial turbulence.
But that's it, and these few flashes of insight are not enough to justify the existence of this book. At times it feels like Paulos simply slapped all of this together to make up for his bad investment decisions. People interested in the subject will find much more valuable reads in the book's index (which includes Mandelbrot and Taleb), than in the actual book itself.
August 19, 2012
I had some insights, but not surprising being a complete layman in the field. Not recommended if you already know something about the stock market, and definitely not if you can't stand it that basic mathematical and statistical facts and calculations are being drawn out endlessly.
November 22, 2020
I am a big fan of John Allen Paulos: he makes math easy to understand, and has an entertaining writing style.
Because of the publication date, some of the examples in this book (WorldComm) are dated, but the basic principles still apply.
Because of the publication date, some of the examples in this book (WorldComm) are dated, but the basic principles still apply.
March 4, 2012
John Allen Paulos [JP] es un matemático que ha escrito fantásticos libros de divulgación de las matemáticas, que recomiendo en bloque. Si encuentran alguno, léanlo. No se arrepentirán. En los 90, JP fue una más de las víctimas de las puntocom. Su experiencia al quedar casi arruinado le llevó a escribir este libro, en el que da un impresionante repaso al mundo de la bolsa, su funcionamiento y las tripas matemáticas que subyacen a la cotización de los valores y las estrategias de inversión.
JP escribe muy bien. Los conceptos que explica son a veces muy, muy complejos, y sin embargo sale airoso cada vez. Le admiro muchísimo. Además, escoge temas que a mí personalmente me parecen muy interesantes. Lo tiene todo.
En el libro aprenderemos sobre conceptos como el efecto ancla, realmente sorprendente: Imaginemos un experimento en el que nos preguntan por un número que no sabemos. Por ejemplo, la población de Uzbekistán. En principio no sabemos qué decir, pero entonces el examinador dice: a ver, ¿es más o menos de 100 millones?. A otro grupo, el examinador les hace la misma pregunta, pero en vez de decir 100 millones dice 1 millón. La media de la gente a la que el examinador les sugirió 100 millones anda por los 60 millones, mientras que la media de los que recibieron la sugerencia de 1 millón ronda los 5 millones. O sea, que nos dejamos influir por una cifra cuando intentamos estimar otra.
Se podría alegar que la gente se dejaba influir por la estimación del experimentador porque suponen que él lo sabe y nosotros no, así que partiendo de su suposición tiramos hacia donde a nosotros nos parece que está la respuesta correcta. Pues no. El experimento se repitió, pero, en vez de una sugerencia del experimentador, ¡se hizo girar una ruleta! La ruleta tenía cifras: 1 millón, 5 millones, 10 millones, 50 millones, 100 millones… Se preguntaba la población de Uzbekistán y se hacía girar la rueda. Las medias de la respuesta de cada grupo estaban sorprendentemente cerca del resultado que había salido en la ruleta en cada ocasión. Impresionante. Lo mismo, dice JP, ocurre cuando vamos a comprar acciones ( o nos hacemos una hipoteca a tipo variable). Si al comprar las acciones éstas están a 60 euros, inconscientemente tomaremos este valor como la “media” de las acciones, de modo que si están por encima estarán bien y si están por debajo estarán mal. Yo hice mi hipoteca con el euribor al 2,1%, más o menos, o sea que ahora que está al 4 lo veo como muy alto. Sin embargo, mirando el euribor de los últimos 20 años, veo que un 4% es bastante bajo (cosa que a la vez me incomoda y me asusta).
Otra cuestión: los sesgos. Nos sentimos más culpables si perdemos dinero por culpa de la acción que por culpa de la inacción. o sea, que si compramos algo y baja nos sentiremos peor que si no lo vendemos y baja, a pesar de que el dinero perdido en cada ocasión será el mismo. En el libro nos cuenta un par de experimentos para reafirmar el concepto.
Escondido en la página 26 encontramos un bello aforismo:
El psicoanálisis es una enfermedad para la que él mismo se postula como cura.
Y también hay una interesante reflexión sobre el concepto de horizonte de complejidad: los seres humanos dejamos de interesarnos por acontecimientos distantes en el futuro, aunque sean muy importantes. Como ejemplo pone una historia estupenda:
Nos encontramos con una lámpara maravillosa, que dentro tiene un genio que nos concederá todo aquello que queramos con una condición: Es necesario ofrecer un dinero por la lámpara, Y hay que venderla tras obtener nuestros deseos por un precio estrictamente menor que el que pagamos. ¿Qué precio ofrecerían, estimados lectores, por la lámpara? Está claro que no podemos ofrecer un céntimo de euro, porque después no podríamos vendérsela a nadie por menos (no valen los medios céntimos ni divisas extranjeras con valores inferiores). Tampoco podemos ofrecer dos céntimos, porque tendríamos que venderla por un céntimo y nuestro futuro comprador no la podría vender, por lo que no la querría comprar. Tampoco podríamos venderla por tres céntimos, porque nuestro comprador se encontraría con que su comprador no podría venderla, y así él no podría venderla, por lo que no nos la compraría… En realidad, siguiendo la cadena, no hay ningún precio por el cual podamos estar seguros de comprarla y luego venderla. Y sin embargo, estamos todos de acuerdo, creo, en que la compraríamos por mil euros. ¿En qué punto deja de importarnos la cadena de compraventas que decide si podremos vender la lámpara o no? Los ecologistas sostienen que algo parecido nos pasa con la conservación del Medio Ambiente: estamos todos de acuerdo en que si seguimos así lo dejaremos todo hecho un desastre, pero como falta mucho y aún hay arbolillos y campos y playas ríos, pues no hacemos todo lo que podríamos.
El libro es fantástico. Tiene partes complejas, pero bien solventadas por el autor, al que, repito, admiro por la simplicidad de sus explicaciones. Me lo he pasado pipa leyendo y encima he aprendido un montón (por así decirlo) sobre economía y bolsa. Es una lectura que merece la pena. Algunas partes requieren esfuerzo por parte del lector, pero es porque los conceptos de debajo son realmente revirados. De regalo, el libro contiene un guión cinematográfico sobre un tipo que sabe matemáticas y unos cuantos chascarrillos que seguro les sacarán una sonrisa. Completito.
Mi nota: Imprescindible.
February 20, 2024
Me he quedado igual... 🤯
Apoyado en la estadística, el mismo acaba diciendo que es factible aplicarla mal y que puede pasar cualquier cosa 🤭.
Y para muestra un botón, su fiasco con Worldcom, que no para de nombrarlo en todo el libro. Tuvo que serle bastante traumático.
Así que ojo👁️, que aunque se pueda predecir e intuir la evolución de la bolsa, siempre puede darse un "cisne negro".🏴🦢🏴
Apoyado en la estadística, el mismo acaba diciendo que es factible aplicarla mal y que puede pasar cualquier cosa 🤭.
Y para muestra un botón, su fiasco con Worldcom, que no para de nombrarlo en todo el libro. Tuvo que serle bastante traumático.
Así que ojo👁️, que aunque se pueda predecir e intuir la evolución de la bolsa, siempre puede darse un "cisne negro".🏴🦢🏴
This entire review has been hidden because of spoilers.
August 24, 2019
Funny, self-effacing, and just a terrific read
Since Professor Paulos delights in paradoxes it is appropriate that a paradox lies at the heart of this very fine book. He does indeed play the stock market, but how well and using what kind of strategy? Ironically Paulos's personal tale is one of obsession and foolhardiness, of buying WCOM at 37 (yes, WCOM), of averaging down again and again and buying calls until in near final desperation our good professor finds himself contemplating with a kind of hopeless hope his WCOM calls at $20 as the stock trades at $1.13! (p. 197)
Interestingly enough, most of what mathematician Paulos writes about here is the psychology of the market and what he learned about himself psychologically as he rode the stallion down, down deep into the valley of despair. Yes, there is some interesting and instructive math included, but how refreshing it is to read a professional academic chronicle his experience while being up-front and personal about the emotional, random, and psychological traps that often guided his decisions. It takes a certain amount of confidence to write a book like this, and it helps a lot to be able to laugh at yourself.
My experience during the period beginning early in 2000 when the market began to tank was similar to Paulos's (which is one reason I found his account so riveting) except (thanking my lucky stars) I did NOT average down as he did, and I certainly did not buy calls. Instead gradually (too gradually of course) I began to take money out of the market. For those of you who lived through those days of shock and despair, Paulos's witty self-examination will be a pleasure to read.
On another level this is a book about market theory. Paulos does not believe in the Efficient Market Hypothesis (EMH), which states that prices in the market accurately reflect the value of the market and that any subsequent deviation (without new information) from those prices is a random walk. His argument (a very persuasive one) is that the market is a self-referential system that depends on how the players view the market. Paradoxically, if they believe in an efficient market they will NOT try to figure out ways to take advantage of anomalies and the market will be inefficient! Conversely, if the players believe that the market is inefficient, that there is some surplus value to be gained, they will indeed look for ways to take advantage of differentials and anomalies, and presto! the market becomes efficient.
Consequently, Paulos' theory is a refinement of the EMH. He sees the market as constantly existing in a dynamic state poised between maximum efficiency and something less than that. He sees the market as a complex system subject to the laws of complexity theory, and like the weather only more so, impossible to predict much in advance.
As for technical versus fundamental analysis, Paulos appropriately hedges. Yes, the trend is your friend, but (e.g.) the full blown Elliot wave theory is "murky" while the fundamentalists suffer from possibly cooked numbers and from the information already being factored into the stock's price. One gets the sense that Paulos is once bitten, twice shy! However, I think he has gotten this exactly right, namely that only a small edge can be had through a lot of work using both approaches.
There are some interesting mathematical paradoxes presented here and some scams. Those of you who have read Paulos's previous books (e.g., Innumeracy: Mathematical Illiteracy and its Consequences, 1988; A Mathematician Reads the Newspaper, 1995, etc.) know he has a gift for making the obtuse and opaque clear, or at least intelligible, and that he can be laugh out loud funny. I thought that he was even funnier here than usual, perhaps because there is a taint of gallows humor infused throughout. For example, in reference to his love affair with WCOM, Paulos writes, "Investing in it had originally seemed like a no-brainer. The realization that doing so had indeed been a no-brainer was glacially slow in arriving." (p. 199)
One paradox is the familiar "All Cretans are liars" upon which Paulos plays a few variations to demonstrate the self-referential aspect which is at the heart of the paradox. Included is this illumination: "The Prosecutor booms, 'You must answer Yes or No. Will your next word be No?'" (p. 187)
One scam is the familiar Ponzi scheme. Paulos thinks of a stock market bubble (as we experienced in the nineties) as a Ponzi scheme in which dot com buyers are hoping to sell to stupider dot com buyers, etc. In another context, Paulos notes perspicaciously, "Even ravaging of the environment may be seen as a kind of global Ponzi scheme, the early 'investors' doing well, later ones less well, until a catastrophe wipes out all gains." (p. 94)
I must warn the reader to beware of many atrocious puns. In one of the "worst," Paulos is explaining the emotional differences between risk adverse people and their opposite and how a stock's beta may be personalized. "A zero beta person would have to be unconscious, perhaps from ingesting too many beta-blockers." (p. 162)
Ouch!
--Dennis Littrell, author of “The World Is Not as We Think It Is”
Since Professor Paulos delights in paradoxes it is appropriate that a paradox lies at the heart of this very fine book. He does indeed play the stock market, but how well and using what kind of strategy? Ironically Paulos's personal tale is one of obsession and foolhardiness, of buying WCOM at 37 (yes, WCOM), of averaging down again and again and buying calls until in near final desperation our good professor finds himself contemplating with a kind of hopeless hope his WCOM calls at $20 as the stock trades at $1.13! (p. 197)
Interestingly enough, most of what mathematician Paulos writes about here is the psychology of the market and what he learned about himself psychologically as he rode the stallion down, down deep into the valley of despair. Yes, there is some interesting and instructive math included, but how refreshing it is to read a professional academic chronicle his experience while being up-front and personal about the emotional, random, and psychological traps that often guided his decisions. It takes a certain amount of confidence to write a book like this, and it helps a lot to be able to laugh at yourself.
My experience during the period beginning early in 2000 when the market began to tank was similar to Paulos's (which is one reason I found his account so riveting) except (thanking my lucky stars) I did NOT average down as he did, and I certainly did not buy calls. Instead gradually (too gradually of course) I began to take money out of the market. For those of you who lived through those days of shock and despair, Paulos's witty self-examination will be a pleasure to read.
On another level this is a book about market theory. Paulos does not believe in the Efficient Market Hypothesis (EMH), which states that prices in the market accurately reflect the value of the market and that any subsequent deviation (without new information) from those prices is a random walk. His argument (a very persuasive one) is that the market is a self-referential system that depends on how the players view the market. Paradoxically, if they believe in an efficient market they will NOT try to figure out ways to take advantage of anomalies and the market will be inefficient! Conversely, if the players believe that the market is inefficient, that there is some surplus value to be gained, they will indeed look for ways to take advantage of differentials and anomalies, and presto! the market becomes efficient.
Consequently, Paulos' theory is a refinement of the EMH. He sees the market as constantly existing in a dynamic state poised between maximum efficiency and something less than that. He sees the market as a complex system subject to the laws of complexity theory, and like the weather only more so, impossible to predict much in advance.
As for technical versus fundamental analysis, Paulos appropriately hedges. Yes, the trend is your friend, but (e.g.) the full blown Elliot wave theory is "murky" while the fundamentalists suffer from possibly cooked numbers and from the information already being factored into the stock's price. One gets the sense that Paulos is once bitten, twice shy! However, I think he has gotten this exactly right, namely that only a small edge can be had through a lot of work using both approaches.
There are some interesting mathematical paradoxes presented here and some scams. Those of you who have read Paulos's previous books (e.g., Innumeracy: Mathematical Illiteracy and its Consequences, 1988; A Mathematician Reads the Newspaper, 1995, etc.) know he has a gift for making the obtuse and opaque clear, or at least intelligible, and that he can be laugh out loud funny. I thought that he was even funnier here than usual, perhaps because there is a taint of gallows humor infused throughout. For example, in reference to his love affair with WCOM, Paulos writes, "Investing in it had originally seemed like a no-brainer. The realization that doing so had indeed been a no-brainer was glacially slow in arriving." (p. 199)
One paradox is the familiar "All Cretans are liars" upon which Paulos plays a few variations to demonstrate the self-referential aspect which is at the heart of the paradox. Included is this illumination: "The Prosecutor booms, 'You must answer Yes or No. Will your next word be No?'" (p. 187)
One scam is the familiar Ponzi scheme. Paulos thinks of a stock market bubble (as we experienced in the nineties) as a Ponzi scheme in which dot com buyers are hoping to sell to stupider dot com buyers, etc. In another context, Paulos notes perspicaciously, "Even ravaging of the environment may be seen as a kind of global Ponzi scheme, the early 'investors' doing well, later ones less well, until a catastrophe wipes out all gains." (p. 94)
I must warn the reader to beware of many atrocious puns. In one of the "worst," Paulos is explaining the emotional differences between risk adverse people and their opposite and how a stock's beta may be personalized. "A zero beta person would have to be unconscious, perhaps from ingesting too many beta-blockers." (p. 162)
Ouch!
--Dennis Littrell, author of “The World Is Not as We Think It Is”
January 29, 2023
Se presentan una serie de reflexiones en torno a temas de la bolsa y a partir de la experiencia del autor sobre su inversión. Así, busca combinar esto con conceptos matemáticos que permitan comprender mejor los aspectos que rodean ese mundo bursátil. No obstante, no logró capturar realmente mi interés.
Creo que pudo tener un enfoque más didáctico, máximo cuando iba a involucrar conceptos de estadística y de esa forma hacerla accesible a todo público (en vez de plantear, en un momento dado, que saltasen párrafos). De igual manera, no vendría mal el uso de imágenes que complementen los conceptos por desarrollar (como cuando define los fractales) o cuidar la formalidad de conceptos (particularmente el de factorial)
Me pareció repetitivo que introdujese un timo que presentó en otro libro y luego lo usara nuevamente de base para contar un historia. Tampoco considero que aportara algo en sí mismo la historia del profesor que escribió la suma de cocientes factoriales (aunque vincula esa suma con la serie y lo que continua presentado, pero no sentí la necesidad de esa anécdota).
Creo que pudo tener un enfoque más didáctico, máximo cuando iba a involucrar conceptos de estadística y de esa forma hacerla accesible a todo público (en vez de plantear, en un momento dado, que saltasen párrafos). De igual manera, no vendría mal el uso de imágenes que complementen los conceptos por desarrollar (como cuando define los fractales) o cuidar la formalidad de conceptos (particularmente el de factorial)
Me pareció repetitivo que introdujese un timo que presentó en otro libro y luego lo usara nuevamente de base para contar un historia. Tampoco considero que aportara algo en sí mismo la historia del profesor que escribió la suma de cocientes factoriales (aunque vincula esa suma con la serie y lo que continua presentado, pero no sentí la necesidad de esa anécdota).
May 19, 2024
There's the germ of a good book in here. A recurring motif in A Mathematician Plays The Stock Market is the author's catastrophic Worldcom trade, culminating in the revelation that, as a mark chasing a loser all the way down, he wrote to that company's CEO with PR "advice" and considered using his position as a respected professor and author to go on CNBC and tout the stock.
Why not make that the focus of the book? Go through the exact details of the trade, the mistakes and cognitive biases that got him there, and discuss the sort of mathematical errors novice investors are likely to make. There's ample material there and it could be helpful.
Instead what we got was a meandering mashup of jokes that aren't particularly amusing and analogies that aren't particularly illuminating. The book lacks focus and I would challenge anyone to tell me the most important thing they learned from it, because for me it all pretty much blurs together. A big disappointment for someone who enjoyed Innumeracy.
Why not make that the focus of the book? Go through the exact details of the trade, the mistakes and cognitive biases that got him there, and discuss the sort of mathematical errors novice investors are likely to make. There's ample material there and it could be helpful.
Instead what we got was a meandering mashup of jokes that aren't particularly amusing and analogies that aren't particularly illuminating. The book lacks focus and I would challenge anyone to tell me the most important thing they learned from it, because for me it all pretty much blurs together. A big disappointment for someone who enjoyed Innumeracy.
January 17, 2022
See raamat tuletas mulle meelde, et mulle meeldib matemaatika. Ja eriti, et numbritega tegelemine on väga loominguline. Lisaks ka seda, et investor peaks börsil tehinguid tehes arvestama ühtviisi nii matemaatikat kui psühholoogiat.
Öeldakse, et mida lihtsamalt oskad keerulisi asju seletada, seda targem sa oled - John Allen Paulosel on just see omadus olemas, et ka matemaatikakaugetele inimestele tõenäosusi ja matemaatilisi tehinguid osata seletada. Lisaks oli see minu jaoks hea meeldetuletus sellistest statistikat puudutavatest mõistetest nagu näiteks standardhälve, kovariatsioon või dispersioon.
Päris algajale investorile seda raamatut siiski ei soovitaks, sest mingi põhi võiks enne teadmiste näol juba olemas olla, et kõigest aru saada.
Öeldakse, et mida lihtsamalt oskad keerulisi asju seletada, seda targem sa oled - John Allen Paulosel on just see omadus olemas, et ka matemaatikakaugetele inimestele tõenäosusi ja matemaatilisi tehinguid osata seletada. Lisaks oli see minu jaoks hea meeldetuletus sellistest statistikat puudutavatest mõistetest nagu näiteks standardhälve, kovariatsioon või dispersioon.
Päris algajale investorile seda raamatut siiski ei soovitaks, sest mingi põhi võiks enne teadmiste näol juba olemas olla, et kõigest aru saada.
November 10, 2017
Tiene algunos capítulos muy buenos, explicando de manera sencilla conceptos básicos del mercado ( o teorías por las cuales le han dado el Nobel a economistas). Otros capítulos requieren una base en estadística, pero aunque la tengas no están tan bien explicados ( en la propia wikipedia puedes encontrar definiciones y ejemplos más claros).
En general un libro agradable de leer e interesante si te gusta el tema.
En general un libro agradable de leer e interesante si te gusta el tema.
July 12, 2019
Nice read for a beginner in the stock market. It's more about psychology than maths, but brings forth some interesting points. The contradiction on the efficient market theory was very enlightening. The whole story about his bad habits and investments in WCOM was interesting and show that even a mathematician can not control his emotions in the market, however it became a bit dull after a while and more diverse examples would have made the book more interesting.
August 26, 2019
I wish I read this book before operating with the stock exchange. John's personal experience and anecdote are kindly explored with fun stories and easy to understand mathematical examples. The style of writing will make you have some smiles while you understand some basics of capital markets (as ways to measure risk, volatility or Expected Value [Mathematical Expectation]) in the skin of an individual operator and Mathematician
July 31, 2019
Solid book, but it's from 2001 time frame and I've seen most of the concepts present it other ways. If you've been in the market and want to try to understand some of the craziness that results this is a good book for it.
May 25, 2021
Thought would be the tale of a Jim Simons-esque maths genius turned millionaire/billionaire.
This is not what I got, however in its place I received several lessons on investing, trading, and the various pitfalls in both. Essential reading
This is not what I got, however in its place I received several lessons on investing, trading, and the various pitfalls in both. Essential reading
January 28, 2022
Ni fu ni fa. Libro breve que deja algún poso a través de los ejemplos de errores que cualquier persona puede cometer a la hora de afrontar una inversión en bolsa. Creemos que tenemos el control y podemos deducir y anticipar pero raras veces es así.
April 22, 2023
Conclusióndel autor:
La inversión en bolsa es un caos inmanejable y no hay recetas para ganar dinero haciendo apuestas a determinadas empresas.
Es curioso que el autor confiese que ha perdido enormes cantidades de dinero comorando acciones.
La inversión en bolsa es un caos inmanejable y no hay recetas para ganar dinero haciendo apuestas a determinadas empresas.
Es curioso que el autor confiese que ha perdido enormes cantidades de dinero comorando acciones.
October 1, 2024
un llibre molt interessant, a estones divertit, terriblement dens i que posa en evidència l'importància de l'atzar davant la terrible dificultat de controlar tots els elements. Per llegir diverses vegades si el volem entendre bé.
May 31, 2017
A lot of the same material as in "Innumeracy", but with examples drawn from his failed investment in WorldCom.
February 18, 2018
this book was more about trading psychology than mathematics.
October 4, 2019
+1 star for keeping it entertaining, another one for being honest about mistakes made; need to be read only if you are still thinking that you can profit from investing in a cherry picked stock.
October 22, 2020
Take care to follow all the suggest method, however a good consideration on how hard it's the stock market and how easy is failing.
Read
July 10, 2021good for making your own mindset on the market.
December 21, 2021
Basic stuff - but a good refresher title to have in your investment collection. More like 3.5 stars
January 6, 2022
The constant referencing of early 2000s WorldCom is dated, the writing & explanations could have been a bit better, but still useful explanations.
Read
April 23, 2022Gelezen in het Nederlands met als titel: een wiskundige op de beurs.
February 9, 2023
Rehashing the well known points, but at least it is an entertaining read.
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