The S&P 500 was down 0.06% to 1,694.49 in afternoon trading Tuesday.
The Dow Jones industrial average was up 0.23% to 15,580.55, while the Nasdaq was down 0.27% to 3,590.64.
The yield on the 10-year Treasury bond rose 0.76% to 2.51%.
The price of gold fell 0.04% to $1,335.50 per ounce.
Irvine-based Broadcom Corp. fell about 4% to $32.01, on concerns that the chipmaker could see less revenue from Cupertino-based Apple Inc. An analyst at Pacific Crest downgraded the company's shares from "outperform" to "sector perform." Broadcom had a recent market value of $18.28 billion.
Irvine disk drive maker Western Digital Corp. was down about 2% to $68.79, a day before the company is set to report fourth-quarter and full-year results. Western Digital had a market value of about $16.26 billion.
San Clemente-based medical device maker ICU Medical Inc. was up about 3% to $70.82, after falling back about 3% on Friday after the company reported disappointing second-quarter results and lowered its guidance for the full year. ICU Medical had a recent market value of $1.04 billion.
Irvine healthcare software maker Quality Systems Inc. shares were off about 2% to $21.89 for a market value of $1.3 billion. Analysts at Raymond James downgraded Quality from "market perform" to "underperform.”
Irvine molecular diagnostics company CombiMatrix Corp. was up about 9% to $3.35 on news that the company signed an agreement with Blue Shield of California for coverage of its testing services. CombiMatrix had a recent market value of $12.01 million.