NEW YORK (Reuters) – Oil tanker operator OMI Corp. yesterday withdrew its $653.8 million bid to acquire rival Stelmar Shipping Ltd. after the unsolicited offer was rejected and Stelmar refused to enter negotiations. OMI, based in Stamford, Connecticut, did not rule out the possibility of a deal down the line, saying it remained ready to open discussions with Stelmar. For now, however, OMI said it had decided against fighting a protracted takeover battle for the Greek shipping company, which rebuffed OMI’s all-stock takeover offer on Monday and altered the company’s by-laws to remove shareholder’s ability to call a special meeting or act by written consent. «Given the Stelmar board’s position and our desire to avoid a costly and protracted process, we have determined that withdrawing our offer is the best course of action,» Craig Stevenson, OMI chairman and chief executive, said in a statement. «If the Stelmar board were to express a willingness to engage in discussions with us, we would be prepared to participate. In the meantime, we will continue to evaluate other options.» The withdrawal brings to a close for now a short-lived but contentious takeover effort that won the support of Stelmar’s top shareholder and founder, Stelios Haji-Ioannou, but failed to sway the company’s board, which said the bid was not in the best interests of its shareholders. Stelmar officials were not immediately available for comment. But Haji-Ioannou, who together with his family control 27 percent of Stelmar’s outstanding stock, said he was «outraged» by the company’s refusal to negotiate and urged the board to reconsider. «Refusing to investigate whether shareholder value can be further maximized must be a breach of the board’s fiduciary duties,» Haji-Ioannou said in a statement. «I do hope the Stelmar board’s refusal even to discuss the OMI offer… are just tactics designed to test the willingness of OMI to improve its offer.» OMI had offered to exchange 3.1 shares of its stock for each outstanding Stelmar share. The combined entity would have been one of the world’s largest publicly traded tanker companies. Stelmar believed that the OMI offer undervalued Stelmar on a net asset value basis, which is a common metric used to value shipping companies, and that its profitability prospects were better as an independent firm since OMI had outlined no cost-saving synergies, people close to Stelmar said. Stelmar shares rose 53 cents to $30.95 in early afternoon trading on the New York Stock Exchange, while OMI shares fell 7 cents to $12.05. Based on closing prices Tuesday, OMI’s offer valued Stelmar at $37.57 per share. Stelmar shares had climbed as much as 31 percent since OMI’s bid was disclosed.