Supertanker freight rates have surged following expanded US sanctions on Russian oil trade, leading to increased demand for alternative fuel supplies in China and India. The newly targeted vessels, known as the 'shadow fleet', have been used to ship oil to these countries, as well as to Iran. Rates for Very Large Crude Carriers (VLCCs) on the Middle East to China route have jumped 39% since Friday, reaching the highest level since October. Shipping rates for Russian oil shipments to China have also doubled due to limited tonnages available. Analysts predict that tanker availability could tighten further as traders seek unsanctioned vessels to ship Russian and Iranian crude.