Indices were up in midday trading on higher oil prices and Berkshire Hathaway’s $1 billion investment in Apple.

The S&P 500 was up 1% to 2,067.27. The Dow Jones Industrial Average was up 1% to 17,715.47. The NASDAQ was up 1.3% to 4,778.46.

The yield on a 10-year Treasury bond was up 2.4% to 1.75%.

The price of gold was up 0.2% to $1,275.

HEALTHCARE

Irvine-based ChromaDex Corp. was up 9% to $5.66 and a $207 million market cap. The ingredients maker’s shares traded by midday at 10 times its 90-day average and are up 21% since Thursday’s well-received quarterly report.

Irvine-based Biolase Inc. was up 8% to $1.35 and a $79 million market cap on moderate volume. The dental laser maker last week reported slightly higher revenue and a lower loss for its most recent quarter.