(Reuters) -U.S. stock index futures slipped and Treasury yields surged on Wednesday amid growing fiscal anxiety as investors focused on discussions around U.S. President Donald Trump's tax-cut bill that has been plagued by Republican infighting.

The gate-keeping House Rules Committee has scheduled an unusual 1 a.m. ET hearing - that is expected to run well into daylight hours - where members will debate the proposed law.

Trump huddled with lawmakers on Tuesday to try to persuade holdouts within his party to get in line on what he calls a "big, beautiful bill", but the visit failed to sway the wide array of lawmakers who object to specific features.

"When tariffs and uncertainty reduce growth, further questions are also raised about how the U.S. federal deficit will be affected by the economy," Daniel Bergvall, head of economic forecasting at SEB said.

At 04:51 a.m. ET, Dow E-minis were down 263 points, or 0.61%, S&P 500 E-minis were down 34.75 points, or 0.58%, and Nasdaq 100 E-minis were down 134 points, or 0.62%.

Highly valued technology stocks took a hit in premarket trading as rising rates tend to discount the present value of future profits.

Nvidia led losses among top megacap and growth stocks and was down almost 1%.

Treasury yields remained elevated, with those on the 30-year note back up to 5% and the benchmark 10-year yield climbing 5.6 basis points to 4.53%.

U.S. bonds have been pressured since the start of the week, when Moody's downgraded the country's sovereign credit rating to "Aa1" from a pristine "Aaa", citing concerns about the nation's growing $36-trillion debt.

Federal Reserve officials said on Tuesday that they expected tariffs to increase prices, but counseled patience before any interest-rate decisions were made.

Among stocks, Wolfspeed tumbled 55.3% to $1.4 following a report that the semiconductor supplier was preparing to file for bankruptcy within weeks.

Palo Alto Networks fell 3.7% after the cybersecurity company reported a 12% increase in operating expenses in the third quarter, along with revenue roughly in line with estimates.

Retailers Target, TJX Cos and home improvement chain Lowe's are some of the major companies scheduled to report earnings before the bell.

The earnings season is almost over, with more than 90% of the S&P 500 having declared results, although AI-poster child Nvidia is set to report next week.

Stocks closed lower on Tuesday, with the S&P 500 snapping a six-day winning streak while the Dow logged its first decline in four sessions.

Despite the losses, U.S. stocks have had a solid month so far. The S&P 500 is more than 17% higher than its April lows, when Trump's reciprocal tariffs roiled global markets.

A pause in the tariffs, a temporary trade truce between the U.S. and China and tame inflation data pushed equities higher, although the S&P 500 is still about 3% from its record highs.

Brokerage Morgan Stanley upgraded its stance on U.S. equities to "overweight", citing a slowing but still expanding global economy despite policy uncertainty.