If I recall rightly, I recall Ballmer mentioning he was actively buying shares...But my recollection may be fuzzy (it was a year or two ago when I recall hearing it).
Actually, unless Ballmer has some grand plan that needs a lot of capital, holding MSFT is not a bad idea at all. With more than 300M shares, he gets a yearly dividend of roughly 350M USD which is only taxed at most 20% as qualified dividend.
Well, even if he needs capital, I am sure he can get debt at much more favorable rate than the tax he would have to pay if he sold the shares. The only argument for selling is if he wants to diversify.
Another example is the Walton family: they still keep >50% ownership of Walmart and live off the dividend.
