* Dollar index rises as greenback taps safe-haven flows
* Lehman bankruptcy protection sparks risk aversion
* Yen rallies broadly, U.S. stocks open sharply down (Recasts, changes byline, dateline, previous LONDON)
By Lucia Mutikani
NEW YORK, Sept 15 (Reuters) - The U.S. dollar rose on Monday as mounting risk aversion after Lehman Brothers Holdings Inc filed for bankruptcy protection sparked some safe-haven flows, while the yen rallied broadly.
Analysts said the greenback, which had dropped in overnight trade, was also being buoyed by a sharp drop in crude oil prices to a seven-month low below $100 per barrel and fears that the U.S. banking problems would spread to other parts of the world.
"The dollar has increasingly been seen as a safe-haven currency and it's exhibiting much of the same type of price action that it exhibited before last August's liquidity crisis set in," said Michael Woolfolk, senior currency strategist at Bank of New York Mellon in New York.
"We are seeing cash temporarily moving into the U.S. dollar amid heightened uncertainty and market turmoil, despite the fact that much of the turmoil is centered here in the U.S. financial markets."
Lehman Brothers <LEH.N> filed for bankruptcy protection, after trying to finance too many risky assets with too little capital, making it the largest and highest-profile casualty of the global credit crisis.
At the same time, the market was also digesting news that Bank of America <BAC.N> had agreed to buy Merrill Lynch <MER.N> and the Federal Reserve would accept stocks in exchange for cash loans for the first time.
In New York morning trade, the ICE Futures dollar index was last up 0.6 percent at 78.800 <.DXY>. The index, which measures the dollar's performance against a basket of currencies rose as high as 79.360 at one point.
The euro <EUR=> slipped 0.2 percent to $1.4197, erasing early gains which had pushed to $1.4479. Rising risk aversion pushed the dollar down 1.9 percent against the Japanese currency to 105.83 yen <JPY=>, the biggest one-day fall since early 2007, while the euro <EURJPY=> dropped 1.9 percent to 150.40 yen.
Seen also as a safe-haven, the Swiss franc rose against the dollar, which fell 0.8 percent to 1.1203 francs <CHF=>.
"It's all about risk aversion with the yen outperforming ... not surprisingly, the high yielders are leading the declines," said Dustin Reid, foreign exchange strategist at ABN Amro Bank in Chicago.
The high-yielding Australian and New Zealand currencies fell sharply versus both the U.S. dollar and the Japanese yen. In Europe, stocks <
> fell more than 4 percent and European credit spreads jumped wider.U.S. stocks fell sharply in early trade.
The uncertainty was so high that major central banks around the world including the European Central Bank, Bank of England and Bank of Japan said they stood ready to help soothe markets.
There is also speculation that the Fed, which holds its regular policy meeting on Tuesday, may cut interest rates again. Rate sensitive Fed funds futures are pricing in an 64 percent chance of rates falling to 1.75 percent from 2.0 percent at the September meeting. <FEDWATCH> (Editing by Tom Hals)