Stocks were mildly higher in choppy trading late Monday. Even blue chips turned positive, but just barely. The Nasdaq and the S&P 500 each rose 0.1%. Meanwhile, the Dow Jones industrial average ticked up a fraction. Volume was again tracking mixed in the stock market today. NYSE trade was running sharply higher, while Nasdaq volume was tracking lower. SunPower (SPWR) shot up 7% to its best levels in more than five years.