Saudi Arabia's largest oil shipping company, Bahri, has temporarily chartered at least five supertankers, increasing the demand for these massive vessels just as their rental prices are rising.

Two of these charters were reported by Tankers International, while additional details came from brokers and a source familiar with the deals. The five very large crude carriers are expected to transport oil from the region to Asia over the next few weeks.

The oil market closely follows Bahri's activities for insights on Saudi oil exports. Shipping companies typically book extra vessels only when they don't have enough ships to handle their own cargoes. Recently, Saudi Arabia launched a significant new gas project that may allow more oil to be available for export, and there are indications that the country's oil shipments are increasing.

Bahri has not yet responded to requests for comment.

These bookings come as supertanker earnings have hit their highest levels in years, driven by a South Korean owner's purchases of tankers. Rates are also rising amid concerns over potential conflicts between the US and Iran, which could affect oil shipments through the Strait of Hormuz, a critical route for about 20% of the world's oil supply.