* Yen hits 16-year high against dollar * U.S. shares weak but off lows on Japan nuclear crisis * Nasdaq turns negative for '11 * U.S. Treasury bonds rally as investors flee risky assets (Updates with yen at 16-year high, U.S. prices)
By Daniel Bases and Al Yoon
NEW YORK, March 16 (Reuters) - U.S. stocks pulled back from their worst levels on Wednesday to mostly hold marginal gains for 2011 while Japan's nuclear crisis spurred yen buying in anticipation that insurance payouts on a disaster that threatens to slow global economic growth.
All three major indexes are up from losses of more than 2 percent, although the Nasdaq stock market is still slightly lower for the year.
Volatility in the market has surged on speculation that damage to nuclear reactors in Japan remains uncontained.
The yen, at one point traded under 80 per U.S. dollar to 79.972 yen <JPY=EBS> on the EBS platform -- within striking distance of an all-time low of 79.75 yen set on April 19, 1995. Speculation that Japanese insurers will have to repatriate yen home to pay for claims was viewed as the main reason for the move.
The chairman of the U.S. Nuclear Regulatory Commission on Wednesday told Congress that the agency would recommend an evacuation area larger than that already in place, also noting that radiation levels are "extremely high."
U.S. Treasury bonds were well bid by investors seeking safety for a third straight day, driving prices up nearly a full points or more and pushing yields down to fresh three-month lows.
Crude oil prices rose steadily on the escalating violence in the Middle East, giving investors another reason to sell riskier equities.
"We are so fixated here on Japan, and this intraday volatility is without question here to stay as we are all quickly learning what nuclear power is. You can throw everything else out the window," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research in Cincinnati, Ohio.
In late New York trade, the Dow Jones industrial average <
> fell 222.32 points, or 1.81 percent, to 11,633.19. The Standard & Poor's 500 Index <.SPX> dropped 22.16 points, or 1.73 percent, to 1,259.71. The Nasdaq Composite Index < > lost 41.07 points, or 1.54 percent, to 2,626.26."Based on the events now, it isn't impossible that the VIX could get up to where it was at the height of the (financial) crisis. It could triple," said Phil Flynn, senior market analyst with PFG Best in Chicago.
The CBOE Volatility Index or VIX, the main index of volatility <.VIX>, rose 18.83 percent to 28.90, its highest level since mid-2010. Earlier, the VIX reached an an intraday high at 31.28 -- up nearly 30 percent from Tuesday's close.
U.S. and European markets also weakened after the U.S. government said its Producer Price Index surged at its fastest pace in more than 1-1/2 years in February.
MSCI's all-country world stock index <.MIWD00000PUS> was down 0.67 percent. Over the past three sessions, the index fell as much as 4.5 percent, following a near 20 percent, two-session dive in Japan's Nikkei average <
>.A 5.7 percent rise in the Nikkei drove the recovery in Asia, though it remained down more than 11 percent for the year.
Europe's Eurofirst 300 <
> dropped 1.6 percent, extending losses to a sixth straight day. Banks led decliners after the Moody's downgrade of Portuguese debt. [ ]TREASURIES, OIL, GOLD HIGHER
Benchmark U.S. 10-year Treasury yields declined to 3.21 percent, after earlier hitting a three-month low of 3.14 percent.
Investors pushed the 10-year Treasury note's price up 28/32 of a point.
Gold prices rebounded after two days of decline. Some focus in the precious metals market shifted back to loose monetary policies and geopolitical tensions, moving away from the nuclear crisis.
Bullion was underpinned by a European Central Bank policymaker's comment that suggested the ECB could possibly delay an April interest-rate hike, and after the downgrade of Portugal by Moody's.
"Now that the dust has settled a little bit and we've had particularly a recovery in energy and other commodities, that's given a tailwind to gold," HSBC analyst James Steel said. "If the focus ceases to be entirely on Japan, and the Middle East again gets some headlines, then the geopolitical risk levels will come back in and support gold."
Spot gold <XAU=> gained 0.15 percent, or $2.10, to $1,396 an ounce
Brent crude for May rose $2.01 to settle at $110.60 a barrel. (Reporting by Daniel Bases and Al Yoon; Editing by Jan Paschal)