AT&T, the $124 billion Dallas-based telephone giant, appointed John Stephens as CFO and senior executive vice president, effective June 1. He will replace Richard Lindner, the company's CFO since 2004, who plans to retire. Stephens, 51, was previously AT&T's controller, a position he held since 2001, and senior vice president. Stephens has worked at AT&T for 19 years in various finance positions, including a stint as vice president of taxes, overseeing corporate tax matters.

Nielsen Co., the $5.1 billion market research company that went public in January, appointed Liz Zale as senior vice president of investor relations. She replaces Rich Nelson, who is now in charge of Nielsen's M&A initiatives in North America. Zale, 42, comes to Nielsen from Moody's Corp., where she was vice president of investor relations. Prior to joining Moody's, she held investor relations and communications positions at DealerTrack Holdings and worked for Columbia University, IBM and Time Warner.

Alliant Energy, a $3.4 billion utility in Madison, Wis., named Thomas Hanson CFO in addition to his current role as treasurer. He succeeds Patricia Kampling, who was promoted to president and COO. Hanson, 57, is a 30-year veteran of Alliant. For the past year, he served as chief accounting officer and treasurer. For three years before that, Hanson was chief accounting officer and controller. Alliant's controller, Robert Durian, 40, will take on the additional title of chief accounting officer.