The Obama administration could announce as early as Tuesday that it plans to expand overtime eligibility for millions of Americans by 2016. The 1938 law that established the federal 40-hour workweek exempts professional, administrative, and executive employees from requiring overtime pay. Under the draft rules, a person classified as a manager or professional that earns $970 a week and works more than 40 hours would have to earn overtime pay, an administration official told Bloomberg.