New York-listed Diana Shipping has secured a higher-paying charter extension with Oldendorff Carriers for one of its post-panamax bulkers. The Greek owner said the 98,704 dwt Polymnia has been fixed at $20,000 per day, minus a 5% commission, for a period running from June 1, 2026, until between March 1 and April 30, 2027. The …