Updates to afternoon levels

By Utkarsh Hathi and Ragini Mathur

May 20 (Reuters) - Wall Street's main indexes rose on Wednesday, as a rebound in chip stocks ahead of Nvidia's quarterly results lifted sentiment after a recent selloff driven by rising bond yields and inflation concerns.

Nvidia NVDA.O, the world's most valuable company and the centerpiece of the global AI boom, rose 2%. The company's results are expected after the closing bell.

Investors will crunch the numbers for signs that appetite for AI infrastructure remains strong enough to support lofty valuations across the technology and AI space.

The broader chip sector also advanced on Wednesday. Marvell Technology MRVL.O rose 7.8%, Intel INTC.O gained 6.3% and Micron Technology MU.O added 3.6%.

The Philadelphia SE Semiconductor index .SOX advanced 2.9%.

"Nvidia's earnings come at just the right time when the market needs some reassurance that the promise of AI can overpower the headwind of rising bond yields," said James Demmert, chief investment officer at Main Street Research.

"The sticking points in Nvidia's earnings report are any signs of margin compression due to rising memory prices, along with how the company is navigating sales in China."

U.S. stocks have come under pressure in recent days as a selloff in global bond markets drove yields higher. Traders were expecting the U.S. Federal Reserve to raise interest rates at the turn of the year as the conflict in the Middle East pushes oil prices higher, reviving inflation worries.

The benchmark 10-year Treasury yield, which touched a 16-month high of 4.687% in the previous session, eased to 4.588% on Wednesday. US/

Brent crude futures LCOc1 extended losses on the day, falling 5.6% to $105.13 after U.S. President Donald Trump said that negotiations with Iran were in the final stages , though investors remain wary about the outcome of peace talks as disruption to Middle Eastern supply continues.

At 11:51 a.m. ET, the Dow Jones Industrial Average .DJI rose 529.35 points, or 1.08%, to 49,894.89, the S&P 500 .SPX gained 72.83 points, or 0.99%, to 7,426.44 and the Nasdaq Composite .IXIC gained 359.73 points, or 1.39%, to 26,230.44.

Seven of the 11 major S&P 500 sectors traded higher, led by consumer discretionary .SPLRCD and technology .SPLRCT, which rose about 1.8% each.

On the flip side, energy .SPNY dropped 1.7% as oil prices fell, while consumer staples .SPLRCS slipped 0.5%.

Target TGT.N shares fell 4%, weighing on staples, after the big-box retailer warned of a challenging macroeconomic backdrop even as it doubled its annual sales-growth forecast. Retail bellwether Walmart WMT.O, expected to report quarterly results on Thursday, was down about 1%.

Due later in the day, minutes from the Fed's latest policy meeting are being awaited by investors for clues on how officials are weighing inflation risks.

Markets are now pricing in about a 37% chance of a 25-basis-point rate hike in December, according to CME's FedWatch tool.

Among other movers, airline stocks were broadly higher amid falling oil prices, with Delta Air Lines DAL.N, United Airlines UAL.O, Southwest Airlines LUV.N and Alaska Air ALK.N up between 6% and 10%.

Intuit INTU.O declined 3.5%. Reuters, citing an internal memo, reported that the company is laying off about 3,000 employees.

Advancing issues outnumbered decliners by a 3.11-to-1 ratio on the NYSE, and by a 2.85-to-1 ratio on the Nasdaq.

The S&P 500 posted 16 new 52-week highs and 15 new lows, while the Nasdaq Composite recorded 62 new highs and 127 new lows.