* Wall Street at records; Dow above 23,000 on IBM boost
* Dollar reverses course, hits session low in late afternoon
* Brent and U.S. crude fall after data (Updates to late afternoon trading, adds commentary)
NEW YORK, Oct 18 (Reuters) - Wall Street again posted record highs on Wednesday, driven by strong earnings, and Treasury yields rose as investors focused on monetary policy, but the dollar slipped to snap a four-day rally.
Long-dated U.S. Treasury yields were higher and the difference between the yields of U.S. 5-year and 30-year Treasuries fell to the lowest level since November 2007 as expectations for tighter global monetary policy put shorter-dated Treasuries under pressure.
Investors focused on global economic strength and expectations for gradual monetary policy tightening as they waited for signals that the European Central Bank would buy fewer bonds, said Paul Christopher, head global market strategist at Wells Fargo Investment Institute in St. Louis.
"Thats equivalent to taking your foot a little bit off the gas but not hitting the brake, he said.
All three Wall Street major indexes posted intraday record highs. Strong earnings from International Business Machines Corp helped the Dow Jones Industrial Average stay above the 23,000 milestone hit on Wednesday for the first time.
"We continue to see solid numbers above expectations, stability in terms of economic growth and global growth," said Omar Aguilar, chief investment officer for equities at Charles Schwab Investment Management.
The Dow Jones Industrial Average rose 158.07 points, or 0.69 percent, to 23,155.51, the S&P 500 gained 3.55 points, or 0.14 percent, to 2,562.91, and the Nasdaq Composite added 8.48 points, or 0.13 percent, to 6,632.14.
Benchmark 10-year notes last fell 11/32 in price to yield 2.3375 percent, from 2.298 percent late on Tuesday. The 30-year bond last fell 30/32 in price to yield 2.8491 percent, from 2.803 percent late on Tuesday.
While the dollar found some support from higher U.S. Treasury yields, the greenback, as measured against six other major currencies, reversed from a small gain to a small decline in afternoon trading.
The dollar index fell 0.1 percent, with the euro up 0.26 percent to $1.1797.
"The market is just trudging along in the absence of any big news or headlines," said Sireen Harajli, FX strategist at Mizuho in New York.
With company results in focus in Europe, the pan-European FTSEurofirst 300 index rose 0.30 percent, and MSCI's gauge of stocks across the globe gained 0.24 percent.
In commodity markets, Brent oil prices retreated from three-week highs reached earlier on Wednesday, after a surprising fall-off in U.S. refining runs and an unexpected increase in inventories of gasoline and diesel.
U.S. crude fell 0.25 percent to $51.75 per barrel, and Brent was last at $57.85, down 0.05 percent on the day.
Gold fell for a third straight session on pressure from a firmer dollar amid speculation that the next chair of the U.S. Federal Reserve could be a policy hawk. Spot gold dropped 0.3 percent to $1,281.16 an ounce.
(Additional reporting by Stephanie Kelly, Dion Rabouin, Saqib Iqbal Ahmed, David Gaffen in New York, Sruthi Shankar in Bengaluru, Danilo Masoni in Milan; Editing by Nick Zieminski and Leslie Adler)