The S&P 500 was up 0.8% in midday trading to 2,092.66.

The Dow Jones Industrial Average was up 0.9% to 17,868.22.

The NASDAQ was up 0.8% to 4,901.43.

The yield on a 10-year Treasury bond was up 0.4% to 1.87%.

The price of gold was down 0.4% to $1,224.

TECHNOLOGY

Irvine-based Western Digital Corp. was up 5.4% to $44.58 and a $12.6 billion market cap. Barclays upgraded Western Digital shares to “overweight” in the memory products maker’s second upgrade in as many days. Western Digital is scheduled to update its guidance, including the $17 billion SanDisk Corp. acquisition, tomorrow after markets close.

SERVICES

Newport Beach-based Acacia Research Corp. was up 5.6% to $5.50 and a $277 million market cap. The patent licensing company’s shares have risen about 15% since Northland Capital upgraded Acacia to an “outperform” rating.

RETAIL

Irvine-based Boot Barn Holdings Inc. was up 9.7% to $7.99 and a $210 million market cap on high volume. The western wear retailer had by midday traded shares at a rate 50% higher than its average and its share price is up 40% since Thursday.