In midday trading on the last trading day of the year, both the S&P 500, at 3,731.78, and the Dow Jones Industrial Average, at 30,407.24, were flat. The Nasdaq fell 0.2% to 12,843.35.
The yield on a 10-year Treasury bond was down 0.9% to 0.918%.
Oil fell 0.4% to $48.20 per barrel.
The price of gold rose 0.2% to $1,897.30 per ounce.
Irvine-based Montrose Environmental Group Inc. (NYSE: MEG) fell 4.7% to $29.80 a share for a market cap of $741 million. Shares in the air quality and environmental services company have nearly doubled since its July IPO at $15 a share.
BJ's Restaurants Inc. (Nasdaq: BJRI) rose 3% to $39.19 and a $875 million market cap. Volume of 103,000 was about a third of its daily average. The shares have climbed about six-fold since their 52-week low in March.