Could Apple buy Microsoft?

Speaking in terms of do they have enough cash yes.

In terms of a realistic transaction, it depends. If Apple decides to buy one of Microsofts business in a market they are not in (like Xbox) they would be fine. With the exception of tablets (Apple licenses their designs to Microsoft) if Apple bought a Microsoft business or Microsoft as a whole they would face serious legal ligation. The DoJ and the European Union would kill them.
If you take a look to the past then you`ll find that at one point Microsoft invested a rather large sum in Apple in order to save the company from falling down when times were bad. This was essentially done as a favor to Jobs and later Apple bought their shares back.

Now, if you ask me "could Apple buy Microsoft as a company" then I will have to say no. Yes. They might have the cash, but Microsoft is an independent firm and the largest competitor, so it would be very unwise to sell. Also, as Justin said, it would violate the Hart Scott Rodino Antitrust Improvements Act,15 USC § 18a and monopolies are not taken lightly by legal forces, making it impossible to happen.

So even if the two companies agreed to merge they can not. At least not according to current laws.
If you're talking cash, no. MSFT has a market cap of $260 billion. Apple has less than half that on hand.

While Apple's cash hoard is rapidly increasing, Microsoft's market cap has also been increasing. At the current rates of each, you'd be looking at mid-2014 at the earliest - and that's assuming:

1. Apple continues to increase its cash hoard at similar rates (and doesn't ever hit a slowdown or decide to do anything else with its cash)
2. Microsoft continues to increase its market cap at similar rates

Both could be affected by positive or negative or neutral changes to either company. The other point is that Apple would likely have to repatriate some or all of its cash to pull off the deal, which would mean that they'd need MUCH, MUCH more than the $260 billion in order to pay taxes on the money.

So, no, not likely for a long time, if ever.

Microsoft market cap is 890 Billion as of this morning. Apple doesn't have that money, especially with the acquisition premium that would come with it.

In other words, both companies have lots of money, are doing well, are doing better every year, and investors believe this is the case, causing the share price to increase. Therefore, until something catastrophic occurs, this transaction couldn't actually take place.

And, even then, no regulatory organization would approve it.

No. Apple's total worth maybe more but their pure revenue is not even close to buy Microsoft. Plus the price of a company is not just their total Net Worth. Market value has a lot of factors and specially a company like Microsoft who is one of the top brand valued company, that number is probably twice or thee times the value of the net worth. So even if Apple wants to buy, they cannot at this point.

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