Is the Postal Service a government agency or an independent entity akin to a private corporation. The legal answer - that it is "an independent establishment of the executive branch of the Government of the United States" - begs the question.
As a government agency, the Postal Service would normally receive government funding to fulfill functions that are deemed socially desirable, such as providing universal service or subsidizing materials for the blind.
On the other hand, as a private corporation, the Postal Service would recover its costs from revenue received from customers (mailers). Those costs would include reasonable prefunding of its deferred liabilities such as pensions and retirement health care. If a private corporation could not raise its prices high enough to cover costs (because demand would drop as customers go elsewhere or stop buying), then losses would have a negative impact on the corporation's shareholders.
But who are the shareholders of the Postal Service?
Mailers are customers of the Postal Service, not shareholders. Printers, mail fulfillment services and other vendors are contractors of the Postal Service, not shareholders. Postal Service executives and workers are employees, not shareholders. Shareholders of private corporations elect a board of directors, but the Postal Service Board of Governors is appointed by the President with the advice and consent of the Senate. So does that make the government the shareholder? That brings us full circle. No wonder we are all confused!
The practical implications of this confusion are everywhere. Should the Postal Service be allowed to "rationalize" its network and close post offices without restrictions? Should the Postal Service's finances be "transparent" for review by regulators - and competitors? Should the Postal Service receive government funds for the electrification of its delivery fleet or for energy-saving improvements to its buildings? Should the Postal Service be exempt from antitrust laws that apply to private corporations? (The Supreme Court said yes; Congress said no.) Should the Postal Service be considered a federal agency to qualify for a "bail out" if that becomes necessary?
https://mailingsystemstechnology.com/article-3194-The-USPS-A-Government-Agency-or-a-Private-Corporation.html