Unsolicited Bid
  
See: Unsolicited Order.
"Not solicited" = "not asked for, tyvm."
It came out of nowhere. The company had no "For Sale!" sign on its front porch. The investor or individual or private equity corporate raider just knocked on the door with a lawyer, served a note and said, "Hi. I want to buy ya." Then a whole bunch of things get kicked off, the biggest of which is that the Board of Directors has to be notified, assuming that this is a real and legitimate bid. That is, if someone sends a registered letter to the General Counsel of Google, who puts his pants on, walks down the hall, and reads it, and it says, "I'm Bob. I want to buy all of the assets of GOOG for $100"...well, that's not legit. But if it's Amazon hitting up Ring to buy them for a bil and change, then the process kicks off. Board is notified. They quickly meet. They decide if they like the bid. They decide if they want to hire a banker to use this bid as a stalking horse to bring higher bids from others. They decide if they want to sell the company at all...maybe they determine it'll be worth 3x as much in 5 years. Whatever the process, they have to pay lawyers to kibbitz with them and cover the legitimacy of the bid, as their core job is to work for shareholders.
If you're ever bored, Google the unsolicited bid that Microsoft made for Yahoo for a huge number...which Yahoo's board turned down, only to have Yahoo eventually sold for scrap at a massively lower number a few years later. One of the great corporate board debacles in history. Frothy reading. Sad end to a once-great company, courtesy of simply bad board management.