The Dow Jones industrial average managed gains in trading Friday, ending the week up 0.5 percent at 10,313, a fifth straight week of good news for blue chips. Markets absorbed positive news from OPEC, as the oil cartel said it was considering a hike in output. Crude prices fell below $43 a barrel, well off summer highs. Shares in Disney were up sharply on news that CEO Michael Eisner would retire at the end of his contract in 2006. In ad-related news, shares in Grey Global Group, which has been hearing bids from suitors, were up 3.3 percent on the week, ending at $940 per share. On the Big Board, Omnicom shares declined 0.6 percent to close the week at $68.90, while IPG’s stock price rose a healthy 5.6 percent to $11.17. WPP, trading as American Depository Receipts on the Nasdaq, were up slightly as the week ended, rising 0.8 percent on the week to hit $46.66.