U.S. stock index futures slipped on Tuesday, with financial stocks edging lower after Moody's overnight cut credit ratings of several small- to mid-sized U.S. banks and said it may downgrade some of the nation's biggest lenders.

Moody's cut the ratings of 10 banks by one notch and placed six banking giants, including Bank of New York Mellon, US Bancorp, State Street and Truist Financial, on review for potential downgrades.

The ratings agency also warned that the sector's credit strength will likely be tested by funding risks and weaker profitability.

Big banks Goldman Sachs and Bank of America eased 0.6% and 0.8%, respectively, in premarket trading, while Bank of New York Mellon shed 1.4% and US Bancorp fell 2.3%.

"The Moody's announcement is a wake-up call," said Stuart Cole, chief macro economist at Equiti Capital.

"U.S. regional banks are the financing life-blood for small and mid-size enterprises, so if they are in trouble and cutting back on lending, then it will have negative growth implications too."

The banking index is down 1.4% so far this year, lagging the 17.7% gains for the benchmark S&P 500 index, after the collapse of Silicon Valley Bank and Signature Bank earlier this year sparked a crisis of confidence in U.S. banks and led to a run on deposits at a host of regional banks.

At 05:08 a.m. ET, Dow e-minis were down 108 points, or 0.3%, S&P 500 e-minis were down 16.5 points, or 0.36%, and Nasdaq 100 e-minis were down 62.75 points, or 0.41%.

All three major indexes kicked off the new week higher on Monday as investors added positions ahead of Thursday's highly awaited U.S. inflation report.

U.S. inflation likely accelerated slightly in July to an annual 3.3%, while the core rate was likely unchanged at 4.8%, according to a Reuters poll of economists.

Remarks by Philadelphia Fed President Harker and Richmond Fed President Barkin will be closely watched for cues about the U.S. central bank's future rate path after mixed messages from New York Fed President John Williams and Fed Governor Michelle Bowman on Monday.

Tesla fell 1.0% in trading before the bell to extend losses from the previous session after finance chief Zachary Kirkhorn stepped down, surprising analysts who saw the company veteran as a possible successor to CEO Elon Musk.

U.S.-listed shares of Chinese companies like Alibaba Group Holding and Bilibili fell between 1.5% and 2.7%, tracking their domestic counterparts after disappointing trade data from the world's second largest economy.

(Reporting by Bansari Mayur Kamdar in Bengaluru; Editing by Sriraj Kalluvila)