A supercharged rally in tanker earnings is attracting new investors to global shipping, as the war in Iran shows how geopolitical crises can curtail vessel supply. Very large crude carriers have seen average daily earnings spike nearly twenty-fold this year.

The Breakwave Tanker Shipping ETF has climbed 3,700% this year. At a shipping finance forum in Singapore, consensus was the market hasn't peaked. "The genie is out of the bottle now," said Philip Clausius, managing partner at Transport Capital.

The world's shipping fleet is expected to generate more than $300 billion in profit this year, versus around $200 billion in 2025, said Abhishek Pandey, Standard Chartered Plc's global head of transportation finance. One-year charter rates for VLCCs have nearly tripled to almost $150,000 a day, according to Veson Nautical. A nearly-new supertanker was resold for a record $200 million, said Matthew Freeman of Veson.

One concern is the rush to build new ships could crater freight rates. The percentage of VLCCs under construction versus the current fleet is 38%, compared to 14% a year ago.