[rchaud]

> Consider a company with value of $1000, with 100 shares outstanding. Each share is $10. Buying back 10 shares, the company spent $100

How would you buy 10% of the outstanding stock of a real company and pay exactly the market price for the entire block? On a public exchange, you'd need to bid higher than the market price for someone to sell you a block that big (otherwise it wouldn't be worth their while to sell).

If you're buying in the public market, other sellers will see that some party is willing to pay above the market price for this stock. They'll raise their own ask price as a result. In private, off-exchange sales, you'll be dealing with seasoned investors (family offices, hedge funds etc) where they're likely to know your situation, and you'll almost definitely pay a premium to acquire that stock.