“the split-strike conversion strategy. Option traders often referred to it as a “collar” or “bull spread.” Basically, it involved buying a basket of stocks, in Madoff’s case 30 to 35 blue-chip stocks that correlated very closely to the Standard & Poor’s (S&P) 100-stock index, and then protecting the stocks with put options. By bracketing an investment with puts and calls, you limit your potential profit if the market rises sharply; but in return you’ve protected yourself against devastating losses should the market drop. The calls created a ceiling on his gains when the market went up; the puts provided a floor to cut his losses when the market went down.”