What company ever sales at their market cap. The MC is considered the minimum sell price for a company but no company is going to sell at their base price. It would take twice as much if not more for Apple to purchase a company like Sony so no Sony, IBM and Disney is out of range unless Apple really want to finance it all with their own money which would also not be very smart. When thinking about how much a company will sell for you have to look at things like net revenue, operating income, and net income.
If you look at Apple revenue compared to IBM, its not even close even though Apple has a bigger Market Cap than IBM. Do you really think IBM is in the ball park for Apple to purchase, if anything its the other way around. Hell, HP and AT&T Market Cap is lower than IBM but their revenue is higher than IBM. I highly doubt any of those companies would sell or can be purchase anywhere close to their market cap.
Even if Apple was willing to pay the exorbent cost that Sony would sell for, the negative impact has to be looked at as well. Sony being a Japanese company, probably would not sit well with the natives to be purchased by a US company.
