Short-Selling Controls Tightened as EU Seeks to Calm Markets

European regulators moved to rein in short-selling, ordering hedge funds and other traders to disclose more information when they bet that stocks will decline and signaling that more restrictions could come soon.

Traders must inform regulators when their net-short positions account for at least 0.1% of a company’s share capital, down from 0.2%, according to the Paris-based European Securities and Markets Authority. The change, which goes into effect after markets close Monday, is being made to give regulators to more information to help with oversight.

“ESMA considers that the current circumstances constitute a serious threat to market confidence” in ...