Excerpts from the article on Loving versus IRS, HERE, authored by law professor Eugene Volokh of the Volokh Conspiracy:

In 2011, responding to concern about the performance of some paid tax-return preparers, the IRS issued new regulations.  Among other things, the new regulations require that paid tax-return preparers pass an initial certification exam, pay annual fees, and complete at least 15 hours of continuing education courses each year.  The IRS estimates that the new regulations will apply to between 600,000 and 700,000 tax-return preparers.

[snip]

… the Executive Branch never interpreted the statute to authorize regulation of tax-return preparers.  But in 2011, the IRS decided that the statute in fact did authorize regulation of tax-return preparers….  We agree with the District Court that the IRS’s statutory authority under Section 330 cannot be stretched so broadly as to encompass authority to regulate tax-return preparers.

[snip]

It might be that allowing the IRS to regulate tax-return preparers more stringently would be wise as a policy matter.  But that is a decision for Congress and the President to make if they wish by enacting new legislation….  The IRS may not unilaterally expand its authority through such an expansive, atextual, and ahistorical reading of [the relevant federal statute.]