When the SEC filing is made, we'll get to see how the deal is structured. The $20 billion from TD Securities becomes a debt obligation of the combined company. There's a tax break in equity to debt conversion, and a second tax break for carried interest. [2]
There may be a preferred stock deal or debt refinancing so that TD gets their $20 billion back. Usually, the private equity firm exits within a few years.
Sure it is. The acquirer is borrowing money for the buyout, and the debt will become a debt of the acquired/merged company. That, by definition, is a leveraged buyout.