May 21 (Reuters) - U.S. stock index futures were subdued on Thursday after Nvidia's ( NVDA ) results failed to impress, while investors awaited retail earnings and key data to gauge the extent of the economic damage from the Middle East conflict.

Shares of Nvidia ( NVDA ), the world's most valuable company, edged up 0.3% in premarket trading after the AI heavyweight forecast second-quarter revenue above Wall Street estimates and announced an $80 billion share repurchase program.

The stock has jumped almost 20% so far this year but the pace of growth has slowed, as investors believe Nvidia ( NVDA ) will face tougher competition, not only from Big Tech but also chip rivals including Intel and Advanced Micro Devices.

"The market's attention is now focused on how long Nvidia ( NVDA ) can sustain this momentum," said Dan Coatsworth, head of markets at AJ Bell. "Growing competition is a key factor weighing on investors' minds, with Nvidia ( NVDA ) no longer in a one-horse race."

Geopolitical factors also remained in focus as Pakistan stepped up diplomatic efforts to accelerate the U.S.-Iran peace talks, while Tehran said it was reviewing Washington's latest response. U.S. President Donald Trump said he could wait a few days for "the right answers" from Iran, but signaled he was prepared to resume attacks if needed.

Brent crude futures dipped 0.7% to $104.21 a barrel on the prospect of talks. [O/R]

The yield on the benchmark U.S. 10-year Treasury note climbed to 4.582%, resuming its recent rise after snapping a three-day streak of gains on Wednesday. A lack of meaningful progress toward reopening the Strait of Hormuz has added to inflation concerns, pushing yields higher.

Markets are pricing in roughly a 40% chance the U.S. Federal Reserve will raise interest rates by at least 25 basis points by the end of the year, according to CME's FedWatch tool.

At 06:00 a.m. ET, Dow E-minis rose 80 points, or 0.16%, S&P 500 E-minis gained 3.75 points, or 0.05%, and Nasdaq 100 E-minis fell 6 points, or 0.02%.

Investors were also monitoring SpaceX after the company unveiled its IPO filing on Wednesday, giving the market a first look at how much billionaire Elon Musk is spending on AI as he bets on transforming the rocket maker into a broader AI-led business.

On the economic front, weekly jobless claims and business activity surveys are due later in the day and could offer investors fresh clues on the health of the economy, with a stronger-than-expected first-quarter earnings season in its final stretch.

Walmart's results, due before the opening bell, will be closely watched as a barometer of consumer spending and the impact of inflation on household budgets.

Among other premarket movers, Intuit shares fell 12.6% after the software maker lowered the annual revenue forecast for its tax-filing software, TurboTax, and said it would cut 17% of its full-time workforce.