BCP Banco Comercial Portugues SA

Portugal's market regulator has banned short selling in shares of Banco Comercial Português SA, as the rescue earlier this week of a major Portuguese lender continues to reverberate through markets.

The regulator said late Wednesday that the ban would take effect on Thursday morning, and will remain in place until 11.59 p.m. The move follows a 15% drop in BCP's share price on Wednesday. BCP's shares were down 11% in early morning trading on Thursday.

The ban comes as investors digest a plan unveiled Sunday night by Portugal's central bank to rescue the country's No. 2 lender, Banco Espírito Santo SA. The lender will be split up into a "good" and "bad" bank and injected with billions of euros of state money.

Write to Jeannette Neumann at jeannette.neumann@wsj.com

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