WASHINGTON: The White House on Wednesday announced the extension of overtime pay benefits to 4.2 million American workers labeled managers but compelled to work long hours for relatively low wages. The move addresses a decades-long trend of businesses requiring 50- and 60-hour weeks of a growing body of workers classified as managers and supervisors but paid barely more than those on low hourly wages. The rule, which comes into force on Dec. 1, is expected to raise the workforce cost for many businesses already facing pressure to increase their minimum hourly pay as well. The action increases the pay threshold below which employees must be paid overtime wages after working 40 hours a week. Held at $455 a week for more than a decade, the threshold will double to $913 a week, the equivalent of nearly $47,500 a year.