Hang up a "Welcome Back" banner and inflate the balloons: In London, one of our nation's three credit-checkers is about to return to the public markets.

If you've ever bought a house, a car, or a cell phone plan, you're probably aware that three major agencies collect your personal financial data. These companies, Equifax (NYSE:EFX), Experian, and TransUnion, sell your data to companies that want to know about you, and resell it back to you whenever you suspect that some unknown baddie is trying to make off with your identity.

Of the three, Equifax is already public, TransUnion is private, and Experian is not quite public. It's currently part of the U.K.-based retail and financial services conglomerate GU.S. Plc., the real subject of this story. GUS has decided to split itself in two sometime within the next year, spinning off Experian as one independent public company, and Argos Retail as another.

Experian, the cash cow of GUS' business, will be saddled with all of the conglomerate's existing debt -- about $3.5 billion worth. To help finance the burden, Experian will conduct a share offering concurrent with or subsequent to its spinoff, diluting its owners by about 10% to 15% right from the get-go, and using the proceeds to either pay off or pay down its inherited debt.

A Reuters story on the breakup quoted a Merrill Lynch analyst as valuing Argos at $7.7 billion, and Experian at as much as $13.1 billion. For the record, that's more than a 22% increase over the total $17 billion value the market currently assigns GUS. But speaking of valuation, if Experian is ultimately valued at $13.1 billion, that would give the firm's shares a multiple of 7.4 times trailing sales. For comparison, Equifax trades for only 3.3 times sales, and Dun & Bradstreet (NYSE:DNB), in a similar line of business, sells for 3.5 times sales.

As currently envisioned, neither Experian nor Argos will list in the U.S. as an ADR. But to be honest, if Merrill Lynch's prediction for Experian's ultimate sales price proves correct, that might be a good thing. I'm all in favor of GUS shareholders getting some value unlocked by breaking their firm up into its constituent parts. But if U.S. investors end up having to pay twice as much for Experian shares as those of similar firms, I'd just as soon have these shares kept offshore and away from impressionable investors.

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Fool contributor Rich Smith does not own shares of any company named above.