Late tech rally boosts Dow

US stocks ended a volatile day in positive territory yesterday with a late-session tech rally, helping markets extend the previous session's SEC certification deadline rally, despite mixed economic data.

According to preliminary reports, the Dow Jones industrial average gained 74.83 to 8,818.14. The Nasdaq composite added 10.82 to 1,345.12. The Standard & Poor's 500 index rose 10.63 to 930.25.

Stocks had dipped at midday following a weak regional manufacturing report, but a second attempt at a tech rally pushed stocks higher in late-afternoon trade.