WASHINGTON (Reuters) - Former U.S. trade official Michael Punke appears to be President Barack Obama's choice to be the next U.S. ambassador to the World Trade Organization, industry officials said on Wednesday. "We hear it from pretty credible sources," said one industry official, who asked not to be identified. "It sounds like it's him. We're just waiting for the White House to make the official announcement." A White House spokesman said he had no comment. U.S. Trade Representative Ron Kirk said on Tuesday he expected Obama to announce his choice for the position soon.