By Davide Barbuscia and Carolina Mandl NEW YORK (Reuters) -Investors are recalibrating how to play U.S. President Donald Trump's whipsawing policy changes, weighing that a so-called "Trump put" supporting stock market prices may be fading and that his administration is more keenly focused on the debt markets.

US stocks lose their footing at the open as tariff and AI worries take hold again. Marvell Technology sees a slowdown in data center business.

U.S. stocks climbed Wednesday after President Donald Trump pulled back on some of his tariffs temporarily. The move revived hope on Wall Street that Trump may avoid a worst-case trade war that grinds down economies and sends inflation higher.