Stocks struggled to find direction early in Friday's session, but jittery traders later decided to take profits from the recent stock run-up ahead of today's derivatives expiration.ig

The S&P 500 was most recently down 16 points to 768 while the Dow Jones industrial average is lower by 111 points to 7,290.

Financials are among the laggards with Bank of America shares lower by 13% and those of JPMorgan Chase down by 5.5%.

Some market watchers blamed comments from Barney Frank, Chairman of the U.S. House Financial Services Committee, for the declines. He said the Federal Reserve's role in the bailout of AIG undercuts the chances of the central bank being granted new powers to monitor the financial system.

Market watchers expected a surge of activity at the end of the session because Friday is a quadruple witching day: one of the four days a year when stock index futures, stock index options, stock options and single stock futures expire simultaneously.

The contracts expire at the end of the session. Dennis Gartman warned investors to beware of sudden movements. We shall see some rather great, perhaps even titanic battles, fought as the options traders on the floors try to get stocks and indices to close at or near 'Big Figure' for the expiry. We shall try our best to stay out of the way, for as elephants play, the mice come under assault, he wrote in Friday's Gartman Letter.

Commodity options and futures also expire on Friday and that has the potential to rattle the commodity-driven Canadian stock market. So far, commodity prices have been relatively stable with oil lower by 27 cents to $51.74 per barrel and gold down $3 to $956 per troy ounce.

The S&P/TSX was most recently lower by 144 points to 8,546. Coming into the session, the index had made gains in eight consecutive sessions.

If U.S. equities are unable to get back above water today, the TSX will be vulnerable to catch-up selling as it still closed Thursday with a gain, but this is not going to be a day for aggressive bets either way, said Andrew Pyle, wealth adviser at ScotiaMcLeod. It's better to wait for the dust to clear.

By Adam Button,; edited by Nick Say,