Bank of America Disputes Goldman Logic on Zero-Day Option Threat to Stocks

The heated debate on the threat posed by the boom in stock derivatives that expire within 24 hours is pitting two of Wall Street’s biggest banks against each other.

After Goldman Sachs Group Inc. blamed the rise of zero-day options for the late-afternoon S&P 500 selloff seen on Aug. 15, Bank of America Corp. dubs the logic “largely misguided.”

At the center of the disagreement: The precise role played by put derivatives that protect against equity losses with a strike price at 4,440, a level close to where the market was trading at that time.

In Goldman’s view, rising client demand for those contracts forced market makers on the other side of the transactions to abruptly hedge their exposures — ultimately leading to a sharp drop in share prices over a roughly 20-minute span.

BofA sees it differently. While trading in those puts added up to almost 100,000 contracts during the session, it was far from a one-way bet.

After breaking up flows into buy and sell orders, strategists including Matthew Welty found customers were net sellers of only 1,000 contracts. Theoretically, that positioning amounted to a bullish stock wager that would have required market makers on a mission to balance their books to snap up shares — rather than, as per Goldman, sell.

“As the S&P sold off market maker hedging needs for the 4,440 put were likely small and in the direction of pushing markets up (not down), exactly the opposite effect of what was claimed,” Welty and his colleagues wrote in a note Tuesday. “High-frequency positioning data from the exchange suggests this is more of a good story than reality.”

Despite the 4440 put having nearly 100K total contracts traded customers were actually net sellers not buyers and of only 1K contracts (roughly 100X smaller than the total volume)