Blackstone is proposing to pay 9.85 euros per share for the Hague-based bank, NIBC said, a 7.8% premium to its closing price on Thursday of 9.13 euros per share.

The lender's shares rose 7.1% at the open to 9.79 euros per share in Amsterdam.

In a statement NIBC said the overture is being supported by its major shareholders, U.S. private equity group JC Flowers and Dutch investment firm Reggeborgh.

NIBC said its boards are considering the proposal, which may not lead to an actual offer, it added.

The bank, which serves 600 small businesses and 400,000 retail clients, reported a net profit of 83 million euros for the first half of 2019. It is due to report full-year earnings Feb. 26.

In its statement, NIBC said JC Flowers, which holds 60.6% of its stock, would agree to sell its stake for 8.93 euros per share under the proposal, while Reggeborgh, which owns 14.6% of the group, would sell its stake for 9.65 euros per share.

JC Flowers bought NIBC from Dutch pension funds in 2005 for 1.8 billion euros, but the financial crisis of 2008 derailed its plans to sell the bank at a profit.

The American firm eventually sought a listing for the bank in 2018, selling a 25% stake at 8.75 euros per share.

(Reporting by Toby Sterling; Editing by David Evans and Jan Harvey)