With an outlook for slumping profits amid squeezed margins, shares of top Asians refiners such as China Petroleum and Chemical Corp (Sinopec), Japan's JXTG Holdings and South Korea's SK Innovation may come under pressure in the coming months.

Spot market freight rates for crude cargoes from the Middle East to Asia recently surged to a record following U.S. sanctions on Chinese tanker companies on Sept. 25. Meanwhile, crude premiums climbed to their highest in years following an attack on Saudi Arabian oil facilities on Sept. 14 that knocked about 5% of global supply offline.

The rising costs could offset an expected boost in refining margins in the fourth quarter from strong gasoil and very low-sulphur fuel oil (VLSFO) demand as ships switch to cleaner fuels to comply with the International Maritime Organization's (IMO) mandate for low-sulphur shipping fuel from 2020.

Sinopec, Asia's largest refiner, is the most vulnerable to the higher freight costs as 70% to 80% of its shipping costs are based on spot rates, Citi's refining equity analysts said, adding the company's 2020 earnings could drop by 5% if margins fall by $3 barrel for a quarter.

Graphic: Asia oil refiners’ shipping costs rise (https://fingfx.thomsonreuters.com/gfx/mkt/12/7594/7525/AsiaShipOct212019.png)

The cost of a supertanker carrying 2 million barrels of crude from the Middle East to China stabilized this week at about $5 a barrel, off from as much as $9 a barrel early last week, said a trader who tracks the rates closely.

That is still more than the about $1.70 a barrel before the U.S. sanctions, the trader said.

"The sharp increase in freight rate will negatively impact the refining margin for Sinopec," Citi Analyst Toby Shek said, adding that the impact was likely to be felt in December because of a time lag from when crude is purchased to when the oil is processed for sale.

Refiners such as S-Oil Corp, SK Energy, a unit of SK Innovation, and Thai Oil Corp are mostly protected from the freight rate surge as 70% to 75% of their crude are shipped on tankers with long-term freight deals, while Formosa Petrochemical ships about 50% of its supply on long-term deals, another Citi Analyst Oscar Yee said.

Share prices for Sinopec, JXTG Holdings, and SK Innovation, the biggest refiners in China, Japan and South Korea respectively, are all down between 23% and 35% from a year ago, Refinitiv data showed.

Japanese refining companies may lower their full-year profit forecasts when they announce results for the July to September period as crude prices were below their expectations, Reiji Ogino, senior analyst at Mitsubishi UFJ Morgan Stanley said in a report issued on Oct. 11.

Brent crude futures fell 8.7% in third quarter as a prolonged U.S.-China trade dispute slowed global economic growth.

Graphic: Share prices for top Asia oil refiners (https://fingfx.thomsonreuters.com/gfx/mkt/12/7575/7506/AsiaOilRefinersOct182019.png)

South Korean refiners are expected to book oil inventory losses and weaker petrochemical margins in the third quarter, offseting an improvement in refining margins since July, said Rho Woo-ho, an analyst at Meritz Securities in Seoul.

Caltex Australia, one of four refineries in the country, reported third-quarter refining margins rose 41% from the previous quarter.

However, the country's dependence on long-haul crude is expected to minimize the gains from the higher margins, Citibank said.

For example, a $6 a barrel rise in freight from Africa to Australia would reduce the company's fourth-quarter refining margins by $2 a barrel, they said.

Graphic: Singapore oil refining margins (https://fingfx.thomsonreuters.com/gfx/mkt/12/7528/7459/MarginsOct182019.png)

(Reporting by Florence Tan in Singapore, Jane Chung in Seoul, Sonali Paul in Melbourne and Yuka Obayashi in Tokyo; Editing by Christian Schmollinger)

By Florence Tan and Jane Chung