"Warren Buffett's Berkshire Hathaway revealed a new position in Nalco Holding (NYSE: NLC); it's my favorite pure play on water filtration," says Chris Mayer in Daily Wealth.

"With a $1.6 billion market cap, Nalco is a small-cap stock, but it's actually one of the world's largest water-treatment companies. Customers use Nalco's products and services to prevent corrosion, contamination, and the buildup of harmful deposits.

"Buffett picked up 8.7 million shares. That makes Berkshire the second-largest shareholder in the company, with a little more than 6% of the shares.It's easy to see what Buffett likes.

Suppose you have a wildly successful business in an ultra hot market. Time to sell?It's probably something to consider. Well, that's certainly the state of affairs in the private equity world.

According to the Wall Street Journal, the founder of Apollo Management LP, Leon Black, is mulling these kinds of cash-out issues [subscription required]. His private equity firm is one of the largest and has done deals such as for Harrah's Entertainment Inc. (NYSE: HET), Realogy Corp. (NYSE: H), and Nalco Holding Co. (NYSE: NLC).

Based on the market multiples -- such as for Fortress Investment Group LLC (NYSE: FIG) -- it looks like he can take home about $1.5 billion selling a minority stake of 10% but still keeping control of his destiny. To me, this is having your cake and eating it too.

What's more, by selling the stake to private investors, there's no need to go through the hassles of the IPO process. In other words, Black has more time to do deals. Although, if the Apollo stock is registered – which is likely to happen – it will become publicly traded within the year.

It's an interesting structure and is typical for small companies. As for Black, he does think out of the box and the back-door IPO does make a lot of sense.

Tom Taulli is the author of various books, including the Complete M&A Handbook and the EDGAR-Online Guide to Decoding Financial Statements.