https://www.reuters.com/article/us-retail-trading-roaringkitty/massachusetts-regulator-subpoenas-gamestop-bull-roaring-kitty-idUSKBN2AA2K2 >Massachusetts securities regulators have issued a subpoena seeking the testimony of a YouTube streamer who helped drive a surge of interest in GameStop Corp as part of a review of his registration, including his "outside business activities," an official said on Wednesday.