To put the market-cap comparison in #msg-101877335 on an apples-to-apples basis, the value of the stock issued in the three mega-mergers should be scaled to PFE’s current share price.
Clearly the ZTS spinoff must be added, but the other divestitures should be in the current value of the company in some way, shouldn't they?
Not really. Much of the proceeds from those deals was offset by share buybacks and increased dividends that wouldn’t have happened if not for the divestitures.