Mom buying Planet Express

Mom has tried to buy Planet Express on three separate ocassions, one of which is definitely canon and two of which are of disputed canon.

Once when Steve Castle was the CEO, another time when Professor Farnsworth sold the company because they'd been losing money. Last, Professor Farnsworth sold the company because the IRS needed him to pay a million dollars in back-taxes, and he couldn't.

Quotes
[Fry & Leela gasp, Bender stutters.] Bender: Also, why are you wearing that funky hat? Professor: Whu? Oh, this? No reason. [He throws it away.] Fry: Hmm. That was odd. Mighty odd. Leela: Are you off your nut Professor? How could you sell the company to Mom? Professor: I had to; we've been losing money. Perhaps my strategy of using a giant space ship to deliver one package at a time wasn't as clever as I thought. Plus you three never actually charged anyone! Fry: Yeah, sorry about that. Leela: [simultaneous] Sorry.
 * Professor: Good news, everyone; I've sold Planet Express to Mom!

[Everyone gasps.] Amy: Oh, no! Hermes: How? Steve Castle: [on screen] I'm gonna sell Planet Express to Mom so she can gut the company and eliminate us as competitors. Mom: [on screen] Don't let the door hit you on the way out, 'cause I don't want ass prints on my new door!
 * Steve Castle: [on screen] Everyone's fired and we're out of business.

Professor: They discovered that I'm 160 instead of 150--ten years older than the age I've been putting down on my tax returns. Fry: Then they should cut you a break! In my day, old people had it easy--senior discount at the movies, senior discount at Denny's, the CBS network... Professor: It's not that simple, Fry. The IRS says that since those ten years are unaccounted for, I have to pay back-taxes! Hermes: How much? Professor: One million dollars! And if I don't come up with the money, I have to declare bankruptcy and sell Planet Express!
 * Leela: What's the problem, Professor?