Mojang reported profits last financial year of $128 million (approx, allowing for conversion rates to USD). Microsoft is trading today on a P/E multiple of 17.

Mojang reported profits last financial year of $128 million (approx, allowing for conversion rates to USD). Microsoft is trading today on a P/E multiple of 17.6. That means, in super simplistic terms, that $128 million in extra profit increases Microsoft's market capitalisation by ($128 x 17.6 =) $2.2528 Billion. Given those profit figures are 6 months old, and the negotiating team would have access to current data, $2.5B is about on the money. Recoup full value != recoup the $2.5B in profit.