By Michael Connor
NEW YORK (Reuters) - The euro sank on Thursday after the European Central Bank unexpectedly cut its ultra-low interest rates even further and said it would start buying loans and bonds next month to prop up the continent's struggling economy.
The move gave the euro, used by 18 nations, its biggest single-day drop since 2011, while boosting the dollar the most against major currencies in more than a year.
Stock prices in Europe climbed to new records, and Wall Street had an early ECB-driven rally, which included new intraday record highs for prominent equity indices. But a late sell-off in energy shares and investor anxieties about U.S. jobs data to be issued on Friday spurred losses for the day.
The Dow Jones industrial average <.DJI> fell 8.7 points, or 0.05 percent, to 17,069.58, the S&P 500 <.SPX> lost 3.07 points, or 0.15 percent, to 1,997.65, and the Nasdaq Composite <.IXIC> dropped 10.28 points, or 0.22 percent, to 4,562.29.
The Standard & Poor's energy industry index <.SPNY> ended off 1.29 percent as oil prices dropped.
"Energy had some pretty dramatic moves today, which goes hand in hand with the strengthening of the U.S. dollar," said Kim Forrest, senior equity research analyst at Fort Pitt Capital Group in Pittsburgh.
Faced with signs of further deterioration in the euro zone economy, the ECB cut interest rates that were already at record lows by another 10 basis points, putting its deposit rate further into negative territory.
The euro zone economy flatlined in the second quarter, and the Ukraine crisis is weighing heavily on business confidence.
The euro hit a 14-month low against the dollar at $1.2921, breaking below the key technical resistance point of $1.30.
Although the euro later pared losses to trade at $1.2944, it was still off 1.55 percent in what was the currency's biggest one-day percentage decline since Nov. 8, 2011.
An index of European shares jumped more than 1 percent <.FTEU3> to its highest level since 2008, and on Wall Street both the Dow and the S&P 500 touched record highs before pulling back.
ECB President Mario Draghi told reporters the bank would buy broad portfolios of simple and transparent asset-backed securities and of euro-denominated covered bonds from October.
The ECB also cut its main refinancing rate to 0.05 percent from 0.15 percent previously and drove the overnight deposit rate deeper into negative territory, now charging banks 0.20 percent to park funds with it.
Spanish, French and Portuguese stocks all gained over a full percentage point <.FCHI> <.IBEX>, while Germany's DAX <.GDAXI> rose 1 percent. The FTSEurofirst 300 index of top European shares hit its highest level since early 2008, at 1,403.63 points, before closing up 1.1 percent to 1,400.99.
The dollar index <.DXY>, which measures the greenback against six major currencies, touched a 2014 high of 83.865, the biggest percentage gain since July 5, 2013. The index was last up 1.1 percent.
The stronger dollar pushed oil prices lower. U.S. crude <CLc1> for October delivery fell $1 to settle at $94.54 a barrel, while Brent <LCOc1> fell 85 cents to settle at $101.89 a barrel.
Benchmark 10-year U.S. Treasuries traded down 12/32 of a point in price, lifting the yield to 2.453 percent.
The Federal Reserve is on the verge of halting its own program of bond-buying, encouraged by a steady stream of stronger data on jobs and growth in the United States. But the jury is still out on when the Fed can raise interest rates.
(Reporting by Michael Connor in New York; Editing by Leslie Adler, Dan Grebler and Chizu Nomiyama)