NEW YORK — Investors can't shake their worries that the economy won't be able to lock in a recovery by the end of the year.

Stocks finished mostly lower after zigzagging yesterday as a mixed outlook on the economy from the International Monetary Fund and falling commodity prices added to a downbeat mood.

After sending stocks soaring during the spring on the belief that the economy was turning around, investors have put their buying on hold since mid-June as several pieces of disappointing economic data eroded the case for a quick recovery.