The S&P 500 increased 0.4% to 4,094.05 in midday trading Friday.
The Dow Jones Industrial Average climbed 0.01% to 33,449.35, while the Nasdaq rose 0.9% to 13,813.69.
Crude oil fell 0.6% to $59.44 a barrel.
Gold was down 0.9% to $1,756.10.
The yield on a 10-year Treasury decreased 1.1% to 1.635%.
Orange County medical device stocks rose in Thursday midday trading, led by San Clemente-based Glaukos Corp. (NYSE: GKOS), which climbed 7% to $85.55 for a $3.9 billion market cap.
Staar Surgical Co. (Nasdaq: STAA) rose 4.9% to $115.54 for a $5.4 billion market cap. Shares of the Lake Forest-based intraocular lens maker have increased three-fold since last April.
Inari Medical Inc. (Nasdaq: NARI) of Irvine was up 2.7% to $114.07 for a $5.6 billion market cap.