Stocks managed only moderate gains heading into the Thanksgiving holiday on Wednesday, even though investors got another taste of strong economic data. The Commerce Department said demand for U.S.-made products rose at a faster rate in October than at any time during the past year. And the Labor Department reported that job claims nationwide fell by 11,000 to 351,000 last week. Market watchers said investors are taking profits as the end of the year approaches. Ad-industry stocks for the short week were mixed. On the Big Board, Omnicom’s shares gained 1 percent to close at $79.43, while IPG’s stock price dipped 3.2 percent to $14.04. WPP, trading as American Depository Receipts on the Nasdaq, rose 2.2 percent to finish at $48.41.