Refusing to take no for an answer, Long Island's North Fork Bancorp sweetened an earlier acquisition proposal for a neighboring institution that has already rebuffed the bank twice.

The Mattituck, N.Y.-based company has offered to increase its January cash offer to buy Farmingdale-based Sunrise Bancorp for 136% of Sunrise's book value, according to a filing with the Securities and Exchange Commission last week.

No specific dollar figure or percentage of book value was discussed in the new proposal, but the earlier deal would have been worth about $85 million.

Sunrise chief executive Joseph Melillo could not be reached for comment.

The new offer was laid out in a letter from North Fork president and chief executive John Adam Kanas to Sunrise chairman Sebastian A. Albrecht.

The $2.7 billion-asset bank also offered to structure the deal in all cash, all stock, or a combination "that would be extremely attractive to your shareholders, as well as your management team and Sunrise's employees generally," according to the letter from Mr. Kanas.

"We are confident that we can formulate a definitive proposal that will offer the greatest value to your stockholders," Mr. Kanas wrote.

The North Fork president requested that if Sunrise explores a merger with other institutions, North Fork should have the same access to confidential information about Sunrise and should have the chance to submit a counterproposal.

And he reiterated his request for a meeting with the board to explain North Fork's offer. That offer remains on the table despite Sunrise's repeated rejections of both the bank's offer and Mr. Kanas' entreaties for a meeting with the board, according to the SEC filing.

"I continue to believe that if given an opportunity to appear before your board, any misunderstandings between our two institutions could be quickly and amicably resolved," Mr. Kanas wrote in the letter.

Meanwhile, the $595 million-asset Sunrise is facing a shareholder lawsuit accusing the thrift's directors of trying to entrench themselves in their positions. The suit also calls for Sunrise to explore merger opportunities.

In a separate filing this week, North Fork also revealed that it has acquired 9.9% of Sunrise's stock. The Federal Reserve had already granted North Fork approval to buy up to that level and had given the bank until Sept. 29 to complete the transaction.

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