U.S. stock index futures declined on Monday following former President Trump's announcement that he would raise the global tariff rate to 15%, after the Supreme Court rejected his "reciprocal tariff" policy.

As of the latest update, Nasdaq futures fell 0.66%, S&P 500 futures dropped 0.46%, and Dow Jones futures declined 0.49%.

Gold prices rose significantly as the new tariff policy heightened market uncertainty regarding inflation prospects and global economic growth. Spot gold increased by more than 1%, while gold futures climbed 2%.

Bitcoin experienced a sharp decline, briefly falling below $65,000 before recovering to above $66,000, though it remained down 1.7%. Heavy selling in cryptocurrencies continues.

These market movements occurred after Trump announced on Saturday that he would raise the global tariff rate from the previously announced 10% to 15%. Trump added that the new tariffs would take effect immediately, though it remains unclear whether any official documents regarding implementation have been signed.

The former president also warned that additional tax measures would be introduced in the coming months.

In a post on Truth Social, Trump stated: "As President of the United States, I am immediately increasing the 10% global tariff on numerous countries to a legally permissible and judicially reviewed 15%. For decades, these countries have been 'exploiting' the United States without consequence—until I took office!"

European officials expressed concern over the move, warning that U.S.-EU trade agreements could be at risk. The European Commission issued a statement on Saturday saying, "The current situation is not conducive to achieving 'fair, balanced, and mutually beneficial' transatlantic trade and investment," and called on the U.S. government to provide "clear explanations" regarding next steps.

Wall Street has just weathered a volatile period. Last Friday, stocks initially rose after the Supreme Court rejected much of Trump's trade agenda, then retreated, before ultimately rallying again. The Dow Jones Industrial Average closed up more than 230 points, a gain of 0.5%, rebounding from an intraday decline of 200 points. The S&P 500 rose 0.7%, and the Nasdaq Composite advanced 0.9%.

Investors had hoped the Supreme Court’s ruling would ease tensions between the U.S. and its trading partners and potentially lead to tariff rebates for affected companies, but they are still awaiting clearer guidance from the White House.

Tim Holland, Chief Investment Officer at Orion Wealth Management, wrote on Friday: "It appears Wall Street—and the general public—will be grappling with trade and tariff issues for some time."

Meanwhile, Iran remains a focus for investors. Last week, Trump urged Iran to reach an agreement on its nuclear program, warning that "something bad" could happen otherwise.

Trump is scheduled to deliver a State of the Union address to Congress on Tuesday.

NVIDIA's earnings report will be a key focus for markets this week. The chip giant is set to release results on Wednesday and is one of only two companies among this year's "Magnificent Seven" tech stocks to have posted gains. The company needs to reassure investors that its artificial intelligence investment strategy remains solid.

On the economic data front, durable goods orders and factory orders figures will be released Monday morning.

Goldman Sachs: Professional investors are preparing for a "potential breakout."

Beneath the market's calm surface, professional investors are buying downside protection with unusual intensity. Latest data from Goldman Sachs shows that although the S&P 500 has traded within one of its narrowest historical ranges over the past two months, institutional trading behavior resembles conditions when the VIX volatility index is at extreme levels of 35—while the VIX currently stands at just 19.

This unusual divergence suggests the market may be on the verge of a directional breakout. The urgency of this defensive positioning stems from approaching key technical levels.

Goldman noted that gamma would turn negative even with a slight decline, coinciding with the trigger threshold for the bank's CTA momentum strategy. Goldman emphasized this is "extremely important," indicating the market may be preparing to reflect the intense volatility that has already been occurring at the individual stock level.

Focus Stocks: Cryptocurrency-related stocks declined in pre-market trading: BMNR fell more than 3%, while Coinbase, Strategy, and TeraWulf each dropped over 2%.

Chip stocks were also lower pre-market: Taiwan Semiconductor and ASML declined more than 1%, Micron Technology fell nearly 1%, and NVIDIA edged down slightly.

Novo Nordisk dropped 13.8% pre-market after its weight-loss drug showed weaker efficacy than Eli Lilly's in the CagriSema trial. Eli Lilly rose 3% pre-market.

Arcellx surged more than 76% pre-market after Gilead Sciences agreed to acquire the company for $115 per share.