A day after notching its strongest gain since 2008, the S&P 500 dropped 3.5 percent on Thursday, highlighting that concerns over tariffs and their impact on economic growth remained persistent.

The stock market’s decline resumed following clarification from the White House that Chinese imports would be subject to a 145 percent tariff, reigniting investor anxiety over the intensifying trade conflict between the United States and China—the world’s two largest economies.

Thursday’s slump wiped out much of Wednesday’s remarkable 9.5 percent surge and underscored lingering fears that aggressive tariff policies could stifle economic progress.

This latest dip continued the recent trend of turbulent trading and significant losses that began after President Trump’s announcement of sweeping tariffs on major trading partners. The erratic movement extended to government bonds, raising concern among policymakers monitoring the stability of this critical segment of the financial system.

Investors had initially responded positively to Mr. Trump’s 90-day delay on certain tariff hikes, which sent markets soaring on Wednesday. However, optimism faded once it became clear the tariff pause excluded China, which was expected to face a 125 percent import tax.