Berkshire Hathaway recently celebrated its 50th anniversary.

Warren Buffett's company, Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B), has been rewarding shareholders handsomely for many decades. (Indeed, the company just celebrated its 50th anniversary, with 40,000-plus shareholders gathering in Omaha for the annual meeting.) Over the past 30 years, its stock has grown by an annual average of 17.3%, and over the past decade, it's been a market-trouncing 10.2%. After all that growth, is it time to take profit in Berkshire Hathaway stock? Should you consider selling?

Well, here are some good reasons to consider selling a stock:

  • If you have little faith in management.
  • If you no longer have confidence in the company's future.
  • If you don't see it having sustainable competitive advantages.
  • If you believe it's significantly overvalued.
  • If you can't remember why you bought or own the stock.

How does Berkshire Hathaway look when you consider questions such as those above? Well, let's take a look.

Berkshire's performance is evidence of talented management. Source: Berkshire Hathaway SEC filings

Management
When it comes to management, it's hard to beat Warren Buffett and his longtime partner, Charlie Munger. Buffett has often been featured on lists of the most admired CEOs, and Berkshire Hathaway has long been near the top of Fortune's Most Admired Companies lists. Buffett is also known for his lengthy and candid annual letters to shareholders, which are not only informative but also educational.

The proof is in the pudding, though, and the fact that Buffett has steered his company to a long-term market-trouncing performance certainly suggests sound stewardship. Berkshire Hathaway's book value per share has averaged 19.4% annually over the past 50 years, vs. just 9.9% for the S&P 500.

Its future
Berkshire Hathaway's future sure seems bright, when you think about its many subsidiaries. As Buffett recently said about its BNSF railroad: "... we move more ton-miles of goods than anyone else, a fact establishing BNSF as the most important artery in our economy's circulatory system." It's unlikely that any new railroads will enter the scene as competitors, and it's hard to imagine BNSF not delivering lots of goods decades from now. Berkshire is also a powerful insurance player, with exceptional financial strength. In tough economic times, it's poised to just grow stronger, taking advantage of rivals' weaknesses. Berkshire has also been beefing up its energy division and is a leader in alternative energies such as wind. It has significant holdings in home-related businesses, too, such as realty offices, manufactured homes, furniture, bricks, insulation, and more. It owns Fruit of the Loom, Dairy Queen, and a bunch of jewelers. If you believe that many years from now, people will still be building, buying, and furnishing homes, and will still need insurance, underwear, ice cream, and jewelry for their loved ones, then you're probably bullish on Berkshire Hathaway's future.

Competitive advantages
A huge competitive advantage is Berkshire Hathaway's business model, which has it taking in billions from its many subsidiaries each year and then deploying those dollars where they can produce the most benefit. Thus, profits from its relatively slow-growing See's Candies business can help pay for new railway cars.

Its various subsidiaries have advantages of their own, too. GEICO, for example, has very low operating costs due to its direct selling model, while subsidiaries such as Benjamin Moore and See's have strong brand names. Berkshire Hathaway itself is an increasingly strong name, and it's now appearing on more of the company's offerings, such as home services.

Buffett himself is a competitive advantage for Berkshire Hathaway.

Valuation
Berkshire Hathaway's stock is far from significantly overvalued. Its recent P/E ratio near 18 is just a bit above its five-year average of 16. Plenty of analysts see it as undervalued at recent levels, too. My colleague Brendan Mathews, for example, recently assessed investments and operating earnings per share and viewed the class-B shares as conservatively worth about $165 each. Their price in mid-May were $145 per share. Even if you view Berkshire as fairly valued or slightly overvalued, that's not enough of a reason to sell, as there would be tax consequences and the company is likely to keep growing over time.

Good reasons to sell
Despite the great long-term promise of Berkshire Hathaway, there are solid reasons to consider selling. For one thing, you might simply need to cash out of some or all of your stocks because you need the money, such as for a down payment. You might also, sensibly, cash out in anticipation of needing the money in a few years, as short-term money isn't too safe in stocks (though they're a terrific place for long-term money). You might have found some much more compelling stock or stocks to buy, ones in which you're expecting to make more money.

If you don't see Berkshire Hathaway as one of your best investment options, then selling is a smart thing to do. But many, if not most, of us would probably do best just hanging on for the long haul.

Longtime Fool specialist Selena Maranjian, whom you can follow on Twitter, owns shares of Berkshire Hathaway. The Motley Fool recommends Berkshire Hathaway. The Motley Fool owns shares of Berkshire Hathaway. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.