(Reuters) - U.S. stock index futures slipped on Wednesday, as megacap stocks were pressured by rising Treasury yields on concerns around the timing of the Federal Reserve's interest rate cuts.

Megacaps such as Apple ( AAPL ), Meta and Nvidia ( NVDA ) dipped between 0.3% and 1.1% in trading before the bell as the yield on Treasury notes edged higher, with that on the five-year note hovering near four-week highs, following a weak debt auction.

Bond yields reflect interest rate expectations. Higher rates mean costlier financing for companies and consumers, which can squeeze on their profits.

The CBOE Volatility Index, a Wall Street fear gauge, also jumped to more than a three-week high of 14.11 points.

The tech-heavy Nasdaq on Tuesday closed above the 17,000 mark for the first time, driven by gains in Nvidia ( NVDA ) and fellow chip stocks, while the benchmark S&P 500 index ended flat with market participants doubting the possibility of an imminent start to Fed's monetary policy easing cycle.

Traders had entered the year expecting a rate reduction at least by March, but with sticky inflation and hawkish comments from central bankers, the majority now appear confident of at least a 25 basis points cut only by November or December, as per the CME FedWatch Tool.

On the data front, focus will be on the central bank's Beige Book, due at 2:00 p.m. ET, that would throw light on the state of the U.S. economy, while April's Personal Consumption Expenditure data, expected later in the week, could offer clues on the Fed's rate cut trajectory.

Markets will also closely monitor comments from this year's voting policymakers, including New York President John Williams and Raphael Bostic through the day.

At 05:49 a.m., Dow E-minis were down 216 points, or 0.55%, while S&P 500 E-minis were down 31.75 points, or 0.64%. Nasdaq 100 E-minis were down 129.25 points, or 0.68%

Marathon Oil advanced 6.1% after a report said ConocoPhillips is in advanced talks to buy the Houston-based company in an all-stock deal for a little over its $15 billion market value.

On the quarterly earnings front, American Airlines cut its second-quarter profit forecast on weaker pricing power, sending its shares down 7.8%. Fellow carriers such as Southwest ( LUV ) and Delta were also down over 1.7% each.

Quarterly results from Abercrombie & Fitch and DICK'S Sporting Goods are also due before the bell, while those from HP Inc, Agilent Technologies and Salesforce are expected after close.

Of the 480 companies in the S&P 500 that have reported earnings as of Friday, 77.9% have surpassed analyst estimates, compared with a long-term average of 66.7%, according to LSEG data.

Robinhood Markets added 3.2% after the trading app maker launched its first-ever share buyback plan.

(Reporting by Johann M Cherian in Bengaluru; Editing by Shinjini Ganguli)