By Inti Landauro

PARIS--French bank Societe Generale SA (GLE.FR) successfully carried out a tender offer to buy out the outstanding shares in Boursorama (BRS.FR) as part of an effort to boost its presence in the online banking sector.

Societe Generale, which already held 55.4% in online bank Boursorama, had offered to pay 12 euros ($16.44) for its outstanding shares in a deal that valued the company at just over EUR1 billion. The offer expired on May 16 after shareholders tendered 20% of the Boursorama shares to Societe Generale, which now directly controls 75% of the online bank, the French stock market regulator said Thursday.

Societe Generale had offered a 22% premium on the share price before the tender offer was announced.

Separately, the French bank signed a shareholders agreement with Spanish bank CaixaBank SA (CABK.MC), which owns a little more than 20% in Boursorama. Together, the two banks now control 95.93% of Boursorama, the regulator said in a statement. This gives them the right to squeeze out minority shareholders and delist the shares.

Boursorama's board had backed the Societe Generale offer.

-Write to Inti Landauro at inti.landauro@wsj.com

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