I checked my Sim’s traits, and sure enough, he has the Shrewd trait for the Fabulously Wealthy Aspiration. I had totally missed that one as my Sim had money when he got it, so it zipped through it in no time. I had to turn right around and get him a different Aspiration.
I also checked Carl’s guide. It stated you get 5% of the household funds every week. I did the math, and that was exactly it! This is going to be great! Now I can’t wait to invest in retail!
As Jimboola11 said, it was really baffling, so it’s good to know! Thanks, everyone, for your answers!