FILE PHOTO - A trader works at his post on the floor at the New York Stock Exchange (NYSE) in New York, U.S., September 12, 2019. REUTERS/Brendan McDermid

(Reuters) - U.S. stock futures fell 0.3% percent when trading resumed on Sunday, a day after attacks on Saudi oil facilities that risk disrupting global energy supplies.

Saturday’s attacks knocked out more than half of Saudi oil output, or more than 5% of global supply.

S&P 500 e-mini futures initially fell 0.59%, but cut their losses and were last down 0.3%.

“I would expect a rough day for stocks tomorrow since this attack largely came out of the blue,” said Nicholas Colas, Co-founder of DataTrek Research. “I’m not overly concerned that it’s more than a one-day move, though. We’re not yet talking about a large-scale military intervention in the region.”

U.S. 10-Year Treasury note futures prices TYv1 rose 0.2 pct at the start of trading.

“It is inconceivable that energy costs don’t rise by some amount worldwide so the long nightmare of disinflation and below target inflation is over, and that’s why the Treasury market is not going to have this flight-to-quality drop in yields,” said David Kotok, chairman & chief investment officer of Cumberland Advisors.