Org. not getting many happy returns?

IRS

Think of the U.S. agency that collects taxes—its initials might remind you of a form you fill out every April, but it’s not known for giving money back.

This clue plays on the idea of "happy returns," which usually means birthday wishes but can also refer to tax returns. The "org." is the IRS (Internal Revenue Service), the U.S. agency that handles taxes—and since people rarely enjoy paying taxes, they’re not getting many "happy" returns. The pun ties the phrase to the IRS’s role in processing tax filings.