If you own a wonderful business...the best thing to do is keep it. All you're going to do is trade your wonderful business for a whole bunch of cash, which isn't as good as the business, and you got the problem of investing in other businesses, and you probably paid a tax in between. So my advice to anybody who owns a wonderful business is keep it.
If you expect to continue to purchase stocks throughout your life, you should welcome price declines as a way to add stocks more cheaply to your portfolio.
If you know how to value businesses, it's crazy to own 50 stocks or 40 stocks or 30 stocks, probably because there aren't that many wonderful businesses understandable to a single human being in all likelihood. To forego buying more of some super-wonderful business and instead put your money into #30 or #35 on your list of attractiveness just strikes Charlie and me as madness.
Accounting consequences do not influence our operating or capital-allocation decisions. When acquisition costs are similar, we much prefer to purchase $2 of earnings that is not reportable by us under standard accounting principles than to purchase $1 of earnings that is reportable.