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Flash Boys: Not So Fast: An Insider's Perspective on High-Frequency Trading
In Flash Boys, Michael Lewis alleged that the entire U.S. stock market is rigged. This is an extraordinarily serious accusation. If it is true that a conspiracy of stock exchanges, banks, regulators and high-frequency traders has rigged the market, this has profound implications for every aspect of our financial system. It’s rather surprising, then, that this book alleging a vast high-frequency trading conspiracy included no high-frequency traders. Flash Boys lacks a single insider’s account, and it shows. Electronic trading is extremely complicated, and if you neglect to talk to any electronic traders, you’re probably going to get it wrong. Flash Not So Fast, written by a former high-frequency trading executive and regulatory compliance expert, provides the missing insider’s perspective on today’s stock market and answers the question of whether or not Michael Lewis is right. Not So Fast reviews the alleged scams described by Lewis and applies the same rigorous analysis that real trading strategies are subjected to, methodically walking through them step by step and explaining what is actually possible in today’s markets and what is not. Extensively researched and documented, Not So Fast provides a clear, accurate picture of how today’s markets operate, including what works, what doesn’t work, and what changes need to be made.
186 pages, Kindle Edition
First published October 29, 2014
52 people are currently reading
654 people want to read
About the author
Peter Kováč
15 books5 followersPeter Kováč (1991)
S atletikou začal v roku 2007 paralelne so začiatkom štúdia na gymnáziu v rodnom Žiari nad Hronom. O desať rokov neskôr začal trénovať pod vedením Štefana Mereša, získal desať titulov majstra Slovenska a v behu na 1500 metrov je súčasťou slovenskej reprezentácie.
V Denníku N začal pracovať v roku 2015 ako webový editor a redaktor športu, o rok neskôr úspešne ukončil štúdium žurnalistiky na Univerzite Komenského v Bratislave. Interným reportérom Denníka N sa stal v októbri 2020, v periodiku je autorom pravidelnej bežeckej rubriky Výklus. Živí sa aj ako fotograf.
S atletikou začal v roku 2007 paralelne so začiatkom štúdia na gymnáziu v rodnom Žiari nad Hronom. O desať rokov neskôr začal trénovať pod vedením Štefana Mereša, získal desať titulov majstra Slovenska a v behu na 1500 metrov je súčasťou slovenskej reprezentácie.
V Denníku N začal pracovať v roku 2015 ako webový editor a redaktor športu, o rok neskôr úspešne ukončil štúdium žurnalistiky na Univerzite Komenského v Bratislave. Interným reportérom Denníka N sa stal v októbri 2020, v periodiku je autorom pravidelnej bežeckej rubriky Výklus. Živí sa aj ako fotograf.
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Displaying 1 - 28 of 28 reviews
June 22, 2016
Ok, this was awesome. If you've ever participated in or read an internet debate and saw one person 'just omg totally pwn' another, this was that. Kovac eviscerated Lewis with a depth that many times felt almost unnecessary, but I ended up going 'Well, ok. He's just committed to being thorough.' It was a great reminder that Lewis is just a storyteller and that, sometimes, he's far more interested in storytelling than in Truth. HFT is super-specialized and Kovac is not just experienced with that part of the financial industry, but he's an amazing debater. And gracious! There were lots of places he bent over backwards to give Lewis and his 'experts' the benefit of the doubt when he didn't have to. Although, to be fair, Lewis had so many holes in his assertions that every time Kovac gave him the benefit, it served as another springboard to describe a different Lewis failure. In the end, I probably retained far less about HFT and the industry in general than I would have liked, but I suspect that will improve with practice. And it wasn't for a lack of teaching quality from Kovac. His book was imminently more understandable to a novice than Lewis' sensational effort was.
February 8, 2015
very good book, clear with concise explanation
Peter Kodak does an excellent work describing the collection of mistakes and / or wrong assumptions made in flash boys. He also manages to explain and give a better sense of how the market works.
Peter Kodak does an excellent work describing the collection of mistakes and / or wrong assumptions made in flash boys. He also manages to explain and give a better sense of how the market works.
September 30, 2019
Unlike "Flash boys", this book does not clash with my personal experience. This book is better sourced, arguments come with more realistic numbers attached and critical dissections are easy to follow. There isn't much repetition either, which is no small feat given how often "Flash Boys" based its conclusion on the same set of mostly-flawed premises.
If you have read "Flash Boys", definitely read this book. If you haven't read "Flash Boys", read this book instead.
If you have read "Flash Boys", definitely read this book. If you haven't read "Flash Boys", read this book instead.
December 30, 2024
Really cool read. Was enough to downgrade Flash Boys to 2 stars. Shows how truly disingenuous Michael Lewis was in his writing and research efforts.
Read
September 18, 2016A fine rebuttal to Flash Boys that is relatively balanced, specific and comprehensive. One is left with an accurate view of the state of financial markets with respect to high frequency trading, and a realization that Flash Boys was garbage.
January 13, 2015
Facts say it all
It was really nice to see a retort to the wild eyed speculation of flash boys. Makes one wonder why the original book had everyone so up in arms.
It was really nice to see a retort to the wild eyed speculation of flash boys. Makes one wonder why the original book had everyone so up in arms.
August 14, 2020
An informative and entertaining rebuttal to Michael Lewis' HFT conspiracy theory; it addresses everything Lewis got wrong, backing assertions up with quantitative data from academic research. If you read Flash Boys, this is a must-read.
February 16, 2016
Randy and I have a friend who has made a fortune off of real estate. He has never invested in any stocks, bonds, mutual funds, etc. because he believes as a Wall Street outsider he'll end up duped. This book makes me believe there's some truth in his stance; Wall Street operates by its own rules — and technology seems to have worsened that situation. A fabulous roller coaster read—eye opening and a bit terrifying.
January 29, 2017
A scathing retort to Michael Lewis' Flash Boys, Kovac's book lays out a compelling point-by-point dismantling of Lewis' story that the entire U.S. stock market is rigged and high frequency traders are to blame. His walkthrough contains numerous footnotes and citations to help bolster his counterargument, something which is conspicuously lacking in Lewis' book. All in all, Kovac's book is convincing enough for me to revise my rating of Flash Boys down to three stars.
June 10, 2016
Peter Kovac, in this book, has argued with guns blazing and literally crushing almost every argument of Michael Lewis in 'Flash Boys'. A lot of his arguments are solid, but sometimes, he becomes too desperate while defending high frequency traders.
If you have read 'Flash Boys', you should also read this chapter by chapter dissection of #1 New York Times Bestseller.
If you have read 'Flash Boys', you should also read this chapter by chapter dissection of #1 New York Times Bestseller.
February 19, 2015
Good complement to Flash Boys. I think the author falls victim to some of the same flaws as Michael Lewis however, namely interpreting facts in the way most favorable to his argument.
October 5, 2015
Refutation of the book Flash Boys written by a HFT practitioner. I found the arguments very convincing, devoid of needless hype or rhetorical flourish. Maybe not as entertaining as Flash boys.
January 6, 2016
good companion to Lewis' book.
April 8, 2020
Must read after reading Flash Boys.
It helped me to understand everything which didn't make sense to me in Flash Boys.
The book is very well researched.
It helped me to understand everything which didn't make sense to me in Flash Boys.
The book is very well researched.
April 14, 2025
“For example, in Chapter 2, Lewis makes an estimate of what he deems to be the cost of high-frequency trading to the markets. It's allegedly $40 billion per year in front-running alone, as measured by a single trade by Thor. I54l In Chapter 6, he tells us that, "Slow market arbitrage...generated more billions of dollars a year than the other strategies combined." Putting this together, these two
"strategies" would then total at least $8o billion a year - more than fifty times higher than the consensus of industry analysts.
Oddly, this number doesn't even square with the estimate Lewis squeezes between these two in Chapter 5: "financial intermediaries" collecting
"somewhere between $10 billion and $22 billion a year, depending on whose estimates you wanted to believe." While we aren't told exactly who Lewis considers to be financial intermediaries, he does tell us that Goldman Sachs in this category, leading one to wonder, as Lewis says, what to believe. [55l
Regardless, even if Lewis had used the industry experts' estimates of $1 - 1.5 billion, it's still a lot of money. But using those real numbers would have led to the inevitable comparisons: RBC alone made half a billion dollars trading equities last year, Goldman made $2.6 billion, JPM made $4.8 billion. I56]”
—-
“That extra money vanished into "the spread." Ten percent of your return disappeared. Poof. This is why the spread is quite important: if it is big, you waste a lot of investment dollars. If you can shrink the spread, your investments earn a lot more.
So, how much has the spread shrunk? Lewis tells us that computerized trading has reduced spreads from a "sixteenth of a percentage point" to "one-hundredth of 1 percent." There are few better techniques to obscure an argument than to make the reader compare fractions. So, let us convert Lewis' fractions into decimal percentages: the spread dropped from 0.0625% to 0.0100%. Put another way, Lewis tells us that the transaction costs to buy and sell your stock dropped six times lower after we moved to a computerized market. That's a pretty powerful argument in favor of computerization. No wonder Lewis buried it under a pile of fractions, and then topped the grave with a non sequitur about liquidity. [44]
Lewis doesn't want to dwell on the possibility that high-frequency market-makers have made the trading costs of the bid-offer spread six times lower for investors. Instead, he quickly launches into a meaningless tangent to say that. increased trading volume doesn't mean better markets. He capably proves this obvious point, and for the rest of the book never touches the argument about vastly reduced trading costs again. It's too bad, because this is quite important.
Smaller spreads are a huge, huge, win for investors. Here's what Vanguard, the world's largest single mutual fund manager, wrote to the SEC on the topic:
"While the data universally demonstrate a significant reduction in”
"strategies" would then total at least $8o billion a year - more than fifty times higher than the consensus of industry analysts.
Oddly, this number doesn't even square with the estimate Lewis squeezes between these two in Chapter 5: "financial intermediaries" collecting
"somewhere between $10 billion and $22 billion a year, depending on whose estimates you wanted to believe." While we aren't told exactly who Lewis considers to be financial intermediaries, he does tell us that Goldman Sachs in this category, leading one to wonder, as Lewis says, what to believe. [55l
Regardless, even if Lewis had used the industry experts' estimates of $1 - 1.5 billion, it's still a lot of money. But using those real numbers would have led to the inevitable comparisons: RBC alone made half a billion dollars trading equities last year, Goldman made $2.6 billion, JPM made $4.8 billion. I56]”
—-
“That extra money vanished into "the spread." Ten percent of your return disappeared. Poof. This is why the spread is quite important: if it is big, you waste a lot of investment dollars. If you can shrink the spread, your investments earn a lot more.
So, how much has the spread shrunk? Lewis tells us that computerized trading has reduced spreads from a "sixteenth of a percentage point" to "one-hundredth of 1 percent." There are few better techniques to obscure an argument than to make the reader compare fractions. So, let us convert Lewis' fractions into decimal percentages: the spread dropped from 0.0625% to 0.0100%. Put another way, Lewis tells us that the transaction costs to buy and sell your stock dropped six times lower after we moved to a computerized market. That's a pretty powerful argument in favor of computerization. No wonder Lewis buried it under a pile of fractions, and then topped the grave with a non sequitur about liquidity. [44]
Lewis doesn't want to dwell on the possibility that high-frequency market-makers have made the trading costs of the bid-offer spread six times lower for investors. Instead, he quickly launches into a meaningless tangent to say that. increased trading volume doesn't mean better markets. He capably proves this obvious point, and for the rest of the book never touches the argument about vastly reduced trading costs again. It's too bad, because this is quite important.
Smaller spreads are a huge, huge, win for investors. Here's what Vanguard, the world's largest single mutual fund manager, wrote to the SEC on the topic:
"While the data universally demonstrate a significant reduction in”
July 14, 2024
An excellent and thorough review of Michael Lewis' Flash Boys. Strongly recommended by Patrick McKenzie, wholly worth it.
It's a useful taxonomy of the kinds of errors made: Lewis misquotes academic research which contradicts him; fails to interview any traders engaged in the industry; is totally unfamiliar with obvious pieces of theory which provide more intuitive, such as price impact; wildlly overgeneralises to a conspiracy from 3 anecdotes; makes frequent, basic mistakes that market participants would not make; and ignores the substantial and widely recognised benefits of lower transaction costs in the industry, which substantially improve the value of consumer investments (up to 25%!).
It's a takedown worthy of Guzey's review of Why We Sleep. It's also an indictment of Lewis' sloppiness, and show how expertise, even in financial markets, can often transfer poorly. Insiders should generally be favoured.
It's a useful taxonomy of the kinds of errors made: Lewis misquotes academic research which contradicts him; fails to interview any traders engaged in the industry; is totally unfamiliar with obvious pieces of theory which provide more intuitive, such as price impact; wildlly overgeneralises to a conspiracy from 3 anecdotes; makes frequent, basic mistakes that market participants would not make; and ignores the substantial and widely recognised benefits of lower transaction costs in the industry, which substantially improve the value of consumer investments (up to 25%!).
It's a takedown worthy of Guzey's review of Why We Sleep. It's also an indictment of Lewis' sloppiness, and show how expertise, even in financial markets, can often transfer poorly. Insiders should generally be favoured.
October 16, 2020
This is more really a critique of Michael Lewis's Flash Boys rather than a book on its own. Recommend to read Flash boys first(although strictly speaking not required) before this one is read. Author does make compelling arguments about HFT firms being market makers and the rigging that Lewis alleges to be more of risk management practices adopted by the HFT firms in addition to normal changes in the markets that can be explained by normal supply demand dynamics.
Basically Lewis says Markets are Black and Peter says Markets are nearly white, the professional traders know they are various shades of grey and by the time it can be figured out the definition of sky is changed.
Basically Lewis says Markets are Black and Peter says Markets are nearly white, the professional traders know they are various shades of grey and by the time it can be figured out the definition of sky is changed.
September 30, 2025
A detailed critique of Flash Boys from someone with industry experience. The writing felt a bit clumsy to me, but the arguments are solid. Best read in parallel with Lewis’s book.
The book language isn’t that brilliant, it’s below even standards of a magazine article.
This book correctly points out to problems in Michael Lewis book, but it’s completely misses the point.
Lewis hits to banks, regulators and government not to hedge funds.
Yes, financial markets are not rigged but they don’t provide real valuation anymore as Peter Kovac rightly points out.
The book language isn’t that brilliant, it’s below even standards of a magazine article.
This book correctly points out to problems in Michael Lewis book, but it’s completely misses the point.
Lewis hits to banks, regulators and government not to hedge funds.
Yes, financial markets are not rigged but they don’t provide real valuation anymore as Peter Kovac rightly points out.
July 28, 2024
Kovac eviscerated Michael Lewis on this one. It was quite technical, but if you’re on the this page, then you probably understand enough about trading and exchanges for it to be worthwhile. Great knowledge, all his arguments were clearly and succinctly made, and Lewis’ arguments fell apart pretty quickly.
August 4, 2024
Devastating takedown of Michael Lewis
I have worked in high frequency trading, as did this author. Lewis has no experience in the field, nor did he even interview high frequency traders to get their side of the story. As his defense of Ponzi schemer Sam Bankman Fried revealed, Lewis is easily taken in by stories he wants to believe.
I have worked in high frequency trading, as did this author. Lewis has no experience in the field, nor did he even interview high frequency traders to get their side of the story. As his defense of Ponzi schemer Sam Bankman Fried revealed, Lewis is easily taken in by stories he wants to believe.
October 21, 2024
A very well-written response to Flash Boys. Peter Kovac does a great job of adding context and nuance to the points made in the original, and does a decent job of simplifying concepts down to an entry-level understanding. Some parts were less beginner-friendly than others, but must of the time that was unavoidable. Overall a solid book!
August 19, 2025
Thoroughly enjoyed reading the book. All the issues around hypothetical leaps in the Lewis book was thoroughly explained!
I wish there was a part 2 to this book around the concerns the author raised around dark pool usage in today’s market and how “public” really are the public markets anymore. A focused discussion around meme stocks would be most welcome!
I wish there was a part 2 to this book around the concerns the author raised around dark pool usage in today’s market and how “public” really are the public markets anymore. A focused discussion around meme stocks would be most welcome!
November 10, 2021
This book does the job to tell some of the truth, but poorly written
October 18, 2022
Sadly much less well known than the book it is criticising, the author sets out to reveal the many misleading arguments made by Michael Lewis. By the end, I was convinced - see if you are too.
March 6, 2023
What the original book should have been
January 31, 2025
Really clean and concise writing that had a clear hypothesis and result to each of Lewis' points. Really enjoyed this read and learned a lot.
January 9, 2017
one cool thing you learn about in this book is "duration risk."
Read
December 11, 2017interesting response to arguments on dangers of trading for tradings sake. Thinking about it
Displaying 1 - 28 of 28 reviews