Stocks held up in early-afternoon action, putting the Nasdaq and S&P 500 on pace for a sixth straight weekly gain. The Nasdaq rose 1%, while the S&P 500 added 0.5%. The Dow Jones industrial average tacked on 0.3%. Volume in the stock market today was tracking down from Thursday's levels across the board. For the week, the Nasdaq and S&P 500 are set for advances of about 0.5% and 0.2%, respectively. The Dow is showing a weekly loss of about 0.2%,