Who ultimately receives the funds when a company is sold?

The owners of the company do, which in this case, the shareholders of the company get the money. When a company is sold off, you are essentially paying a price for the shares of the company. So depending on your shareholding in the company, i.e. the number of shares you own, you will get the money (most likely) in the same percentage/fraction as your ownership.

Needless to say, this varies if someone sold their shares, so as to enable the buyer to acquire a majority stake or controlling stake in the company.

Either way, the shareholders get the money.