When companies do buybacks they don't control the shares they buyback, the shares disappear. The market cap of the company decreases because they know have less

When companies do buybacks they don't control the shares they buyback, the shares disappear. The market cap of the company decreases because they know have less assets but the stock price doesn't because the cap is split over less shares. Either way, the market cap theoretically decreases by the amount paid out.