GLOBAL MARKETS-U.S. stocks weak on Ambac; euro falls vs dlr

(Recasts with U.S. markets, adds byline; changes dateline; previous LONDON)

By Herbert Lash

NEW YORK, April 23 (Reuters) - U.S. stocks were mostly lower on Wednesday as new worries about bond insurer Ambac dragged down financial shares, offsetting optimism about technology sector earnings, while the euro posted its biggest drop against the dollar in three weeks.

Oil eased from a record high of nearly $120 a barrel on Tuesday after crude oil stocks in the United States rose more than expected last week.

The euro fell as soft economic data and comments by European policy-makers indicated a weak U.S. currency is hurting economic growth in the euro zone, curbing expectations that the European Central Bank will further increase interest rates.

Ambac Financial Group(ABK.N: Quote, Profile, Research) on Wednesday posted a surprising wide first-quarter loss, and its shares plunged 41.6 percent to $3.52 amid worries about its outlook.

Financial shares declined 1.2 percent as investors fretted anew about the impact of the subprime mortgage fallout.

"Ambac lost more money than people thought," said Al Goldman, chief market strategist at Wachovia Securities in St. Louis. "That was kind of a shock to the system, but I think that is a worry that will be on the back burner soon."

The Nasdaq, however, rose on strong results from chipmaker Broadcom (BRCM.O: Quote, Profile, Research) and expectations that iPod maker Apple (AAPL.O: Quote, Profile, Research) will deliver robust earnings when it reports after the bell on Wednesday.