https://www.reuters.com/article/us-usa-wechat-shanghai/u-s-firms-in-shanghai-say-wechat-ban-could-hit-competitiveness-revenue-survey-idUSKBN25M15N >U.S. companies based in the financial hub of Shanghai said Washington's planned ban on Chinese messaging app WeChat could badly hit their competitiveness and revenue should it apply to U.S. firms and citizens in China, a survey showed on Wednesday.