On any other day, this $7.5 million trade for 50,000 options contracts might have briefly hurt stock prices, though not caused much of a ripple. But coming on a day when all varieties of financial markets were deeply unsettled, the trade may have played a key role in the stock-market collapse just 20 minutes later.
The trade by Universa, a hedge fund advised by Nassim Taleb, author of "Black Swan: The Impact of the Highly Improbable," led traders on the other side of the transaction—including Barclays Capital, the brokerage arm of British bank Barcl
In the disarray, some huge superfast-trading hedge funds that now provide much of the liquidity for the stock market pulled to the sidelines. The working theory among traders and others involved in the exchange meltdown is that the "Black Swan"-linked fund may have contributed to a "Black Swan" moment, a rare, unforeseen event that can have devastating consequences.