"Over at the SEC, a spokesperson said the agency can allocate civil penalties to one of three places: the general fund at the U.S. Treasury, the Treasury's Investor Protection Fund (which is used to help fund awards granted to whistleblowers), or another separate fund used to repay harmed investors."

According to this, fines are not allocated to the Commission to finance further enforcement activity except that funding awards to whistleblowers might lead to more enforcement actions. Keyword: might

https://www.marketplace.org/2022/08/12/where-does-money-coll...

"What Does the SEC Do With Money It Collects From Fines?

This will depend on the nature of the penalty. If investors or others were harmed financially due to a transgression, the penalties collected will be used to recover those losses and make those investors whole. Until the passage of the Sarbanes-Oxley Act of 2002, all penalties the SEC obtained were paid to the United States Treasury.

Section 308 of the Sarbanes-Oxley Act, the so-called "Fair Funds provision," permits the SEC to request that certain penalties be added to any disgorgement fund established as part of an SEC enforcement action to return money to shareholders, investors, whistleblowers, or other victims of the defendant's securities law violations."

https://www.investopedia.com/ask/answers/05/secfines.asp

HN commenters seem to pay particular attention to Matt Levine's ramblings. Here he is dispelling the myth:

"It is not literally the case that the US Securities and Exchange Commission is a for-profit business whose goal is to maximize its revenue, and whose most important source of revenue is fining financial services companies for their misdeeds. But that is sometimes a tempting way to think about things."

https://www.bloomberg.com/opinion/articles/2023-02-02/the-se...