The S&P 500 rose 0.62% to 1,786.39 in afternoon trading Monday.
The Dow Jones Industrial Average was up 0.84% to 15,887.99, while the Nasdaq was up 0.67% to 4,027.97.
The yield on a 10-year Treasury bond rose 0.38% to 2.88%.
The price of gold was up 0.79% to $1,244.30 per ounce.
Irvine-based disk drive maker Western Digital Corp. was up about 3% to $81.51 for a market value of $19.26 billion. An analyst at Citigroup upgraded the ratings on Western Digital and Cupertino-based rival Seagate Technology Inc. from "hold" to "buy" on what appears to be a recovery in the PC market.
Seagate shares were up about 3.5% to $51.74 for a market value of $16.87 billion.
Costa Mesa-based printed circuit board maker TTM Technologies Inc. shares were off about 8% to $7.87 for a market value of $650.44 million. The company announced on Monday a $150 million public offering of convertible senior notes due 2020.
Huntington Beach-based action sports apparel manufacturer and retailer Quiksilver Inc. was up about 4% to $8.57 for a market value of $1.44 billion.
New York equity research firm Monness, Crespi, Hardt & Company Inc. initiated coverage of the company with a "buy" rating and an $11 price target based on the company's potential for higher margins, the firm said. That follows an upgrade from B. Riley & Co. last week from "neutral" to "buy" following the company's October quarter, which saw adjusted earnings before interest, taxes, depreciation and amortization up $3 million from the year-ago period and up $7 million for the second half of Quiksilver's fiscal year.