U.S. stock futures traded in a mixed fashion Wednesday, with weakness in the tech sector continuing as investors fretted over the sustainability of sky-high stock valuations.

At 05:55 ET (10:55 GMT), Dow Jones Futures gained 28 points, or 0.1%, while S&P 500 Futures slipped 18 points, or 0.3%, and Nasdaq 100 Futures fell 120 points, or 0.5%.

The main U.S. averages slumped on Tuesday, as the broad-based S&P 500 declined 1.2%, the blue chip Dow Jones Industrial Average dropped 0.5%, and the tech-heavy NASDAQ Composite slumped 2%.

Bank CEOs stoke market bubble fears

The slide came after the CEOs of banking giants Morgan Stanley (NYSE:MS) and Goldman Sachs (NYSE:GS) sounded alarm bells over overheated valuations and speculative trading in technology shares.

Morgan Stanley boss Ted Pick said markets could face a drawdown of 10%-15%, adding that such a pullback would be a healthy normalization after months of exuberance driven by artificial-intelligence optimism.

Goldman Sachs head David Solomon echoed those concerns, warning that the surge in mega-cap tech stocks had created “bubble-like dynamics” that were unsustainable without stronger earnings support.

Their remarks stoked investor anxiety that Wall Street’s rally, powered by the “Magnificent Seven” tech giants, may be approaching a breaking point. Several of those companies have seen market capitalizations soar to record highs this year, fueling fears of excessive concentration risk.

ADP data in spotlight

These warnings came as investors also faced growing uncertainty about the Fed’s next policy steps. A prolonged government shutdown has left key economic data releases unavailable, depriving policymakers and traders of crucial signals about the state of the economy.

Fed officials on Monday added to the confusion. Some policymakers suggested that the central bank could consider another cut in December if inflation continues to cool, while others argued that strong job growth and resilient demand meant policy should stay restrictive for longer.

With this in mind, today’s private jobs report for October from payrolls processor ADP will be studied carefully.

“This formerly discredited release is back in fashion, given that we have no official jobs data,” said analysts at ING, in a note. “Expectations are for a modest increase at +30k after last month’s 32k fall. An on-consensus reading today … would maintain doubts about whether the Fed cuts again in December.”

AMD, Pinterest add to tech selloff

The tech selloff has seen weakness in a number of names in premarket trading Wednesday.

Advanced Micro Devices (AMD) (NASDAQ:AMD) stock dropped over 4% as a spike in sales and profit at the AI chipmaker was overshadowed by darkening sentiment around elevated tech valuations.

Pinterest (NYSE:PINS) sock tumbled roughly 18% after its quarterly revenue guidance fell short of expectations, stoking worries about a slowdown in digital advertising.

The earnings season continues Wednesday, with numbers from burger giant McDonald’s (NYSE:MCD) due before the open.

Of the 360 S&P 500 companies that have reported thus far, roughly 82% have beaten expectations, according to FactSet data. 

Crude bounces after selloff

Oil prices bounced Wednesday after the previous session’s weakness as a large build in U.S. inventories sparked fears of sluggish demand. 

Brent futures gained 0.7% to $64.90 a barrel, having touched a near two-week low in the prior session, and U.S. West Texas Intermediate crude futures rose 0.8% to $61.03 a barrel.

Data from the American Petroleum Institute, released late Tuesday, showed U.S. oil inventories grew 6.5 million barrels in the week to November 1, blazing past expectations for a 2.4 million barrel draw. 

This has sparked concerns, especially if confirmed by official data later Wednesday, over sluggish U.S. fuel demand, especially as an ongoing government shutdown disrupted air travel in large swathes of the country.