The philosophy being sound is worthless if the execution is flawed. As to investing look at page 35-36. It’s not literally just T-bills, but treasury holdings

The philosophy being sound is worthless if the execution is flawed. As to investing look at page 35-36. It’s not literally just T-bills, but treasury holdings with very low interest rates compared to the kinds of investments private companies are allowed to make. https://about.usps.com/who-we-are/financials/10k-reports/fy2018.pdf https://about.usps.com/who-we-are/financials/10k-reports/fy2...