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.

Why Warren Buffett was selling stocks, Marvell’s outlook fails to wow Wall Street, and more news to start your day.

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.