We study a set of trading restrictions imposed by Robinhood and other retail-oriented broker-dealers in 38 stocks, including GameStop. Restrictions limit equity and/or options positions. Stock price effects are large, with CARs averaging -13.54% within two hours after a stock’s first trading...

By 2012, all European Union countries began requiring the disclosure of large short positions. This regime change reduced short interest, bid-ask spreads, and the informativeness of prices. After specific disclosures, short-run abnormal returns are insignificantly negative, but 90-day cumulative...