(Updates market action, adds quote)

NEW YORK, March 17 (Reuters) - The yield on U.S. 3-month Treasury bills fell below 1 percent on Monday to levels not seen in 50 years prompted by intense safety bids for cash spurred by the ongoing global credit crunch.

Investors were pulling money out of stocks and even the booming commodity market even after the Federal Reserve conducted a fresh round of measures over the weekend to alleviate the credit crisis.

Major U.S. stock indexes .DJI.SPX.IXIC were down as much as 1 percent. Oil prices CLc1 were off 2.6 percent at $107 a barrel.

“People are confused. They are in a reactive mode,” said Lou Brien, market strategist at DRW Trading in Chicago.

The yield on three-month T-bills, considered by economists as a "risk-free" benchmark return on U.S. assets, was last quoted at 0.84 percent US3MT=RR, down 36 basis points from late Friday. It reached a low of 0.63 percent earlier.

“It’s a complete place to hide out,” Brien said.

The yield on 1-month Treasury bills US1MT=RR traded even lower than their three-month counterparts. It was last quoted at 0.55 percent, down 64 basis points from late Friday.

Six-month bill yield US6MT=RR last traded at 1.23 percent, compared with 1.34 percent late on Friday. (Reporting by Richard Leong, editing by Walker Simon)