Diana Shipping (DSX) said Genco Shipping & Trading (GNK) has shifted its valuation approach in assessing Diana's fully financed, all-cash $24.80-a-share offer, citing a move away from broker-based net asset value estimates Genco used for years.

Diana said Thursday its proposal is roughly equal to Genco's net asset value under the VesselsValue broker valuations Genco previously used, while comparable take-private deals in the sector over the past five years have typically closed at about 82% of NAV.

The company called on Genco to participate in an independent valuation process and to remove its shareholder rights plan to allow investors to evaluate the offer directly.

Diana urged shareholders to tender their shares before the offer expires June 26.

Genco did not immediately respond to a request for comment from MT Newswires. The company previously rejected the Diana offer as inadequate.