Shipper Navigator Holdings Ltd expects continued demand for petrochemical gases in the fourth quarter to make up for a fall in liquefied petroleum gas (LPG) shipments caused by the slump in oil prices, a senior executive told Reuters.

Navigator, backed by billionaire-investor Wilbur Ross, expects a utilization rate of about 97 percent for its fleet despite the weak oil market, and is in line with its ten-year average, Chief Financial Officer Niall Nolan said.

The shale boom in the United States has resulted in an abundance of LPG, a byproduct of oil refining and natural gas production, and large quantities are being shipped overseas.

But the 60 percent drop in global crude prices since June has squeezed opportunities for traders to profit from moving LPG from the United States to Europe, where LPG was costly. That has hurt Navigator and its rivals.

Shares of Navigator, in which Ross has a 40 percent stake, have lost more than a third of their value since June. Rivals StealthGas Inc and Dorian LPG Ltd have declined 42.5 percent, on average, in the same period.

Navigator’s fleet of 25 vessels ship petrochemical gases such as ethylene, used to make plastics, vinyls and resins, besides LPG and ammonia.

The petrochemical industry has seen strong growth over the past decade, driven by the availability of cheap raw materials and robust demand from the plastics and construction industries in Asia.

“It’s the ability to shift between LPG and petrochemical gases that enables us to maintain not only our utilization, but our rates as well,” said Nolan.

North America has been vying with the Middle East to be the top supplier of LPG, mostly butane and propane used for heating, cooking and increasingly in transport.

Navigator shares were trading down 6.5 percent at $16.15 in afternoon trading on the New York Stock Exchange.