Millions of retirees will receive their January Social Security checks, worth up to $4,873 per check for those who retire at 70 years old, in three days. Retirees who were born from the 1st through the 10th of their respective birth months will receive the regular monthly check for January from the Social Security Administration on Jan.

Advocates say the Social Security Fairness Act rights a decades-old disparity, though it will also put strain on Social Security Trust Funds, which face a looming insolvency crisis.

For decades, Americans have seen lower Social Security checks if they fall into the circumstances under the WEP and GPO.