(Adds U.S. market open, byline, dateline; previous LONDON)
* MSCI world stocks index in biggest 2-day sell off in 6 months Dollar off 3-yr low as U.S. yields steady at near 4-yr high
By Herbert Lash
NEW YORK, Jan 30 (Reuters) - World stocks declined in their biggest two-day dive in almost six months on Tuesday as tumbling oil prices and a jump in global borrowing costs cooled the year's euphoric start in financial markets.
Lackluster German inflation curbed a rise in U.S. Treasury yields - the benchmark for world lending rates - after they touched their strongest level in nearly four years overnight at 2.733 percent.
Stocks on Wall Street shed almost 1 percent, led by a decline in energy shares amid ongoing evidence of rising U.S. crude output.
A plunge in healthcare-related companies also pulled stocks lower after Amazon.com, Berkshire Hathaway and JPMorgan said they plan to form a venture to cut costs for their U.S. employees.
The S&P energy sector fell 1.77 percent and healthcare tumbled 1.55 percent, the second-biggest decline among the 11 major sectors.
Health insurer UnitedHealth and drugmaker Pfizer were among the top five decliners in the S&P 500, falling 3.3 percent and 2.6 percent, respectively.
Pfizer had risen about 2 percent in pre-market trading after the company's quarterly results and full-year forecasts beat expectations.
Investors initially were spooked by the two-day decline on Wall Street, which prompted a flight to the safety of U.S. government bonds, said Gennadiy Goldberg, interest rates strategist, at TD Securities in New York.
But the Treasury price rally tapered off as investors readied for President Donald Trump's first State of the Union address to Congress later on Tuesday, a Federal Reserve statement on Wednesday and a jobs report on Friday that serves as a barometer of the U.S. economy.
The Fed will be watched for comments that could quicken the pace of expected interest rate hikes this year as the inflation outlook has firmed in recent readings.
"Investors are getting a bit worried about inflation, which has led some people to believe that the Fed might be more aggressive when it comes to raising rates," said Robert Pavlik, chief investment strategist at SlateStone Wealth.
"Despite this selloff, all indications point to a firming economy and I do expect to see some bargain hunters step in soon," Pavlik said.
On Wall Street, the Dow Jones Industrial Average fell 294.98 points, or 1.12 percent, to 26,144.5. The S&P 500 lost 24.69 points, or 0.87 percent, to 2,828.84 and the Nasdaq Composite dropped 49.97 points, or 0.67 percent, to 7,416.54.
The pan-European FTSEurofirst 300 index lost 0.73 percent and MSCI's gauge of stocks across the globe shed 0.86 percent.
Benchmark 10-year notes fell 4/32 in price to yield 2.7142 percent.
The dollar reversed Monday's gains. After six straight weekly declines, the dollar index was on track to fall about 3.4 percent for the month, which would be its biggest monthly fall since March 2016.
The dollar index fell 0.03 percent, with the euro up 0.07 percent to $1.239. The Japanese yen strengthened 0.06 percent versus the greenback at 108.92 per dollar.
Brent crude futures fell 90 cents to $68.56 a barrel, while West Texas Intermediate futures slid $1.28 to $64.28 a barrel.
Expectations for U.S. crude inventories to rise for the first time in 11 weeks may also be keeping oil under pressure, according to a preliminary poll by Reuters on Monday.
"The global trend seems to be indicating more oil is coming into the market despite best efforts by the Saudis and Russians to curtail output," said John Kilduff, partner at Again Capital LLC in New York.
Reporting by Herbert Lash; Editing by Nick Zieminski