US stock indices closed mixed on Monday, reflecting growing uncertainty in investor sentiment. The S&P 500 dipped slightly by 0.07%, the Nasdaq 100 made a modest gain of 0.03%, while the Dow Jones Industrial Average declined by 0.37%.

Meanwhile, the Chinese stock market posted its strongest rally in three years as optimism grew over potential new measures to combat deflation and stimulate economic growth. Copper futures rose in response to President Donald Trump's latest tariff threats. The Shanghai Stock Exchange Index climbed 0.4%, hitting its highest level this year, while the CSI 300, a key benchmark of mainland Chinese equities, approached its highest level since December.

New data released Wednesday show China's industrial sector has been mired in deflation for 33 consecutive months, though consumer prices unexpectedly rose in June. This sets the stage for the upcoming July Politburo meeting in Beijing, where investors are anticipating stronger policy actions following recent government pledges to cut excess industrial capacity.

Experts note that China's anti-inflation campaign, aimed at curbing overproduction, could support global trade and stock markets if implemented effectively. By reducing deflationary pressure and improving corporate margins, these efforts could also help ease trade tensions by limiting the export of ultra-cheap Chinese goods.

Despite the rally in China, broader Asian markets declined along with futures on the S&P 500 and Nasdaq. Investor appetite for risk remained subdued after Trump reignited trade fears. US Treasury yields fell for the fifth straight session as global demand weakened, coinciding with a week crowded with bond auctions. The US dollar saw a slight uptick.

Elsewhere, traders adopted a cautious stance, reflecting on the implications of escalating trade disputes and waiting for clues about the future direction of stocks after last week's record highs. On Tuesday, Trump renewed his push for aggressive tariffs, sending warning letters to countries such as South Korea and Japan.

The US president reaffirmed plans to implement sweeping import duties starting in early August, making clear there will be no further extensions for exemptions. He also announced a proposed 50% tariff on copper imports and hinted at delaying a crippling 200% tariff on foreign-made pharmaceuticals for up to a year, giving the industry time to adjust.

In a separate development, Trump warned that continued frustration over EU-imposed taxes and fines on US tech companies might prompt him to unilaterally impose a new tariff on European goods within the next two days, despite progress in broader trade talks with the bloc.

From a technical perspective, the key objective for S&P 500 buyers today is to break above the immediate resistance level of $6,223. A successful breach would open the door to a rally toward $6,234. Further upside momentum would require securing control over the $6,245 mark, which would strengthen the bulls' position. On the downside, if risk appetite continues to weaken, buyers must defend the $6,211 support level. A failure to hold this ground could send the index sharply lower to $6,200, potentially exposing it to a further decline toward $6,185.