Trump Media’s Truth API market-data service is encountering pushback from parts of Wall Street even after signing some trading firms as customers. People familiar with the matter said several firms, including Hudson River Trading and Citadel Securities, do not want to pay for the feed because they do not see it as essential to trading operations. The debate has drawn attention beyond the product itself because analysts say current insider-trading rules do not explicitly cover a sitting president using a media platform he owns to publish potentially market-moving information, or selling faster access to that information. Karen Woody, a professor at Washington and Lee University School of Law, said the regulatory system was not built with that scenario in mind. SEC (U.S. securities regulator) Chair Paul Atkins previously said in an interview that the agency is monitoring developments related to the Truth API data stream.