Well for example.. IC-DISC + Roth IRA can be used in a way which bypasses contribution limits when combined with a Roth IRA and has some tax advantages.

I know this is a thing because executives in a company where I was in leadership were doing it. Too shady for my taste, but there was a well-oiled industry of accountants and lawyers ready to implement it (despite acknowledging that combining IC-DISC with Roth IRAs could look questionable at that time.. maybe still does).

It almost got closed in 2017 and 2021 but Unfortunately it appears to still be a thing. https://www.plantemoran.com/explore-our-thinking/insight/202...

Executives and/or owners of closely held companies can set up a parallel IC-DISC (Interest Charge - Domestic International Sales Corporation) as a sort of shell company and then transfer as much business income to the DISC as allowed (based on international sales) via "commissions". There is no tax assessed to the parent company on the transferred funds.

Some owners of DISCs use their Roth IRA account to buy the DISC before dumping money into it. It's then possible to bypass the contribution limit and amass huge amounts of money in the Roth IRA, far more than a normal person could.

https://www.investopedia.com/taxes/what-disc-tax-break-and-c...

https://www.forbes.com/sites/greatspeculations/2017/03/01/co...

With a self directed IRA you can buy pretty much anything. No you don't have to be an accredited investor, and even if you do, under trump's tax rules you just need to pass a test.