Bank stocks and the broader markets were volatile Friday because of "quadruple witching" — a day on which contracts for stock index futures, stock index options, stock options and single stock futures all expire.

The KBW Bank Index fell 0.36%, but ended the week up 4.15%. The Dow Jones industrial average fell 0.37% and the Standard & Poor's 500 fell 0.26%.

Economists at Wells Fargo Securities said in a note Friday that since World War II the pace and character of consumer spending has defined the U.S. economy but that this could change, with implications for economic recovery.

"If the American consumer has truly changed her spots and become a greater saving, less credit-using more bargain-hunting species, then what will be the character of this recovery and the longer-run pace of economic growth?" the economists wrote.

Decliners included JPMorgan Chase & Co., off 0.02%; Wells Fargo & Co., 1% SunTrust Banks Inc., 0.3%; Marshall & Ilsley Corp., 0.9%; Capital One Financial Corp., 1.5%; Regions Financial Corp., 2.2%, and Citigroup Inc., 16 cents a share, to $4.26.

Gainers included Bank of America Corp., up 0.1%; PNC Financial Services Group Inc., 0.7%; U.S. Bancorp, 1.4%; BB&T Corp., 1.2%; KeyCorp, 1.2%; Fifth Third Bancorp, 0.9%; Comerica Inc., 1.5%, and Zions Bancorp., 0.7%.

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