GLOBAL MARKETS-Lehman storm hammers dlr, stocks in risk flight

* Investors run from risk after Lehman files for Chapter 11

* High-grade debt, gold, yen in demand on banking stress

* Fed, ECB, BoE turn on liquidity taps

* Focus turns to Fed policy decision on Tuesday (Changes dateline, byline, adds quotes update prices, PVS HONG KONG)

By Veronica Brown

LONDON, Sept 15 (Reuters) - Stocks and the U.S. dollar sank on Monday after Lehman Brothers (LEH.N: Quote, Profile, Research, Stock Buzz) filed for bankruptcy protection, with a broad flight from risk igniting U.S. Treasury debt, gold and the low yielding Japanese yen.

Adding to the mix of ingredients feeding the latest financial storm, American International Group Inc (AIG.N: Quote, Profile, Research, Stock Buzz), one of the world's largest insurers, was reported to have asked the U.S. Federal Reserve for a $40 billion bridge loan, and the Fed expanded its liquidity provision facilities.

U.S. stock market futures SPc2 DJc2 NDc2 were down between 2 and 3.5 percent, pointing to a sharply lower open, while European stocks fell 3.6 percent in early trade. Amongst them, Lehman Brothers shares in Frankfurt tanked 83 percent (LHMH.F: Quote, Profile, Research, Stock Buzz).

Turmoil on Wall Street, just a week after the U.S. government bailed out troubled mortgage agencies Fannie Mae and Freddie Mac, sparked a violent wave of risk aversion through all asset classes.

The dollar tumbled 2.7 percent versus the yen, setting the Japanese currency on track for its biggest daily gain since early 2002.

Fed fund futures jumped to indicate a 86 percent probability of a U.S. interest rate cut to 1.75 percent on Tuesday from 2 percent currently [FEDWATCH].

Classic financial market safe-haven gold jumped more than 2 percent while U.S. Treasury yields, which move in the opposite direction to prices, fell to multi-month lows.

"What we're seeing is a rise in risk aversion because nobody really knows if there is a systemic problem in the U.S. financial system," said Lutz Karpowitz, forex strategist at Commerzbank.