Stocks continued to hold modest gains near Wednesday halftime, as they bounced back from losses in the past two sessions. The Dow Jones industrial average gained 0.6%. The Nasdaq and S&P 500 rose 0.5% and 0.4%, respectively. Volume was tracking higher on the Nasdaq and a little lower on the NYSE volume. Regeneron Pharmaceuticals (REGN) climbed 4%, regaining all of Tuesday's loss and then some. The stock slumped as much as 7% intraday Tuesday