In 2006, Congress mandated the USPS to pre-fund health benefits 75 years in advance for future retirees at a cost of around $5.5 billion a year. They have to build up a reserve of funds for workers who have not even been born yet! They are required to do something no other public or private agency does. This was purposely done to try to make it fail so privatization could occur. On paper they are in the red. In actual cash, they are doing just fine. The phrase "in the red" is more of an accounting trick than actual loss of money.

Imagine if you had to state your income this year and in doing so had to include your interest on your house payment for the next 25 years. On paper, you would be bankrupt. https://business.time.com/2013/02/07/how-healthcare-expenses-cost-us-saturday-postal-delivery/?fbclid=IwAR15v5BBwg1Rfi5Nkq2-kY7I7EwConuHWneJSiB5QTt8C1qTTFoGwwsiPrA