The newfound confidence investors showed at the start of the year held up through the end of January, boosting cash flows into stock mutual funds to the highest levels in more than a decade.

By one measure, the funds attracted cash at the fastest pace in 17 years. The $34.2 billion of net deposits in stock mutual funds and exchange-traded funds for the four weeks ended Jan. 30 was the largest four-week total since January 1996, Lipper reported.