MADRID--Spain's Caixabank SA (CABK.MC) on Friday said its offer for Banco BPI SA (BPI.LB) is fair and will stay on the table despite being rejected by the Portuguese lender's board.

In a regulatory filing, the Barcelona-based bank said it only plans to review the situation after its current takeover offer is finalized--an announcement that quashes hopes for a raised bid for now.

Caixabank offered in February 1.09 billion euros ($1.21 billion) for the 55.9% of BPI that it doesn't already own, at EUR1.329 a share in cash.

Shares of BPI closed Thursday at EUR1.46, and BPI's board said that under its calculations the bank is valued at EUR2.04 a share. That excludes an extra EUR0.22 a share from synergies expected under the merger. Therefore, BPI said, "it doesn't recommend that its shareholders accept the bid."

BPI's stock has risen sharply this week after another shareholder publicly rebuked the Caixabank offer and said BPI should consider merging with Portuguese lender Banco Comercial Portugues SA (BCP.LB) instead.

Isabel dos Santos, Africa's wealthiest woman and BPI's second-largest shareholder with a 18.6% stake, said a merger with Banco Comercial Portugues would create a large domestic lender with operations in Angola, Mozambique and Poland and a diversified shareholder base.

Write to David Roman at david.roman@dowjones.com

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