I just rounded down (to give a conservative estimate) the $7.5bn I've seen everywhere. If they are giving them new MSFT shares worth $7.5bn, buying those shares back would cost around $7.5bn assuming the price doesn't move. Of course it may be significantly more or less that depending on the evolution of the stock price.
By the way, I said they will buy back stock in the next six months but it will be in the six months following the closing of the transaction (which is expected to take place by the end of the year). I've edited my previous comment slightly.
By the way, I said they will buy back stock in the next six months but it will be in the six months following the closing of the transaction (which is expected to take place by the end of the year). I've edited my previous comment slightly.