(For a Reuters live blog on U.S., UK and European stock markets, click or type LIVE/ in a news window.)

* Dow, S&P, Nasdaq futures flat

Jan 23 (Reuters) - U.S. stock index futures were subdued on Tuesday, with investors now awaiting a peak in the earnings season and economic data in a major test for Wall Street's sustenance of a recent rally that saw the S&P 500 scale record highs and enter a bull market.

Megacap stocks lost some ground in premarket trading, with Apple, Alphabet, Amazon.com and Meta Platforms down between 0.2% and 0.3% as U.S. Treasury yields rose.

The benchmark S&P 500 touched a fresh intraday record peak and closed at an all-time high for a second session on Monday, extending a bull-market run, fueled by strength in megacap tech and chip stocks.

The blue-chip Dow also surpassed the 38,000-point mark for the first time on Monday, gaining for the third trading day.

"Waning inflation, moderating interest rates and relatively stable earnings projections for 2024 present a positive backdrop for equities," said Eric Freedman, chief investment officer at U.S. Bank Asset Management.

"The strength in U.S. equities in recent months is anchored to the notion that progressively softening economic conditions and decelerating inflation will allow the Federal Reserve to take a more dovish stance as the year unfolds."

The personal consumption expenditure (PCE) index - the Fed's preferred inflation gauge, S&P Global PMI readings and an advance fourth-quarter GDP print this week will be key to assess the central bank's next policy decision when it meets on Jan. 31.

Wall Street had lost steam at the start of 2024, struck by a mixed bag of inflation data and Federal Reserve policymakers clamping down on market speculation of interest-rate cuts arriving as early as March this year.

Traders' expectations of U.S. monetary policy easing have now deferred to May, with an 84% odd for an at least 25 basis point cut, as per CME Group's FedWatch Tool, from earlier expectations of March.

Earnings from some of the major companies like Procter & Gamble, Johnson & Johnson, General Electric , Lockheed Martin, D.R. Horton and Halliburton are due before the market open.

Among others, Netflix, Texas Instruments and Steel Dynamics are set to report after markets close, while Tesla, Intel and American Express are due later this week.

All eyes are on the profit outlook for corporate America after major U.S. banks kicked off the ongoing earnings season, which has been mixed so far, with lower profits.

So far, 84.6% of the S&P 500 companies that have reported results have surpassed earnings expectations, LSEG data showed on Friday, compared with the 93.1% beat seen in the previous week.

United Airlines gained 6.5% following an upbeat full-year outlook, steering 2.4%-3% gains in other airline stocks such as Delta Air Lines, American Airlines Group and Southwest Airlines.

At 5:31 a.m. ET, Dow e-minis were down 20 points, or 0.05%, S&P 500 e-minis remained unchanged, and Nasdaq 100 e-minis were down 4.5 points, or 0.03%.

Cryptocurrency and blockchain-related stocks including Coinbase Global, Bitfarms, Riot Platforms and Marathon Digital declined between 2.4% and 4.2% after bitcoin fell below the $40,000-mark, hitting a more than seven-week low. (Reporting by Ankika Biswas; Editing by Maju Samuel)