Howard Schultz to Step Down as Starbucks Chairman

Former CEO to write book on coffee chain’s social-impact work; Myron Ullman to become next chairman

Howard Schultz is stepping down as chairman of Starbucks Corp., the international behemoth he built that transformed the way Americans drink coffee.

The move is likely to fuel speculation that the liberal-leaning Mr. Schultz is preparing to run for political office.

For most of the past three decades, Mr. Schultz was the public face of the...