Born as a five-and-dime, evolved into the world's largest discount retailer and, most recently, into a retailer-cum-grocer, Wal-Mart (NYSE:WMT) seems intent on taking over increasingly large swaths of the American economy. Its latest ventures? Banking and health care.

Back in July 2005, Wal-Mart petitioned the Federal Deposit Insurance Corporation for permission to open an industrial bank. The stated aim of that venture was to keep "in-house" the fees that Wal-Mart currently pays other people's banks to process its credit and debit card payments -- consequently reducing Wal-Mart's operating costs and permitting it to reduce its prices even further. (While I'd normally look askance at a company's argument that it intends to pass savings on to customers, in Wal-Mart's case, that's an integral part of its strategy to undercut the selling prices of rivals like Target (NYSE:TGT), Costco (NASDAQ:COST), and Sears Holdings (NASDAQ:SHLD).)

Which isn't to say the company has no ulterior motive. If its application to open an industrial bank is approved, the company can, theoretically at least, expand into retail banking after three years, without seeking any additional approval from the FDIC. That possibility has small community banks feeling mighty nervous, and even larger banks the size of, say, a BB&T (NYSE:BBT) probably don't relish the prospect of added competition.

Would you like some health care with that?
As the saying goes, misery loves company. Getting ready to keep the bankers company in their misery, then, are insurers such as Aetna (NYSE:AET). That's right, folks. Welcome to Wal-Mart HMO.

According to a press release issued on Friday, Wal-Mart will begin offering health insurance to businesses on Jan. 4. The initiative will be marketed jointly by Wal-Mart's warehouse club, Sam's, in conjunction with a private company by the name of ExtendBenefits, a six-year-old company and already the self-described "leading provider of individual and family benefits solutions to corporate America."

Businesses will be able to contract with Sam's Club to offer their employees access to a new program called "ExtendChoice." Through it, employees can use tax-free dollars to purchase HMO, PPO, and HAS (health savings account) plans. The best part of the program: Once purchased, the plan becomes the employee's property and is portable from employer to employer in the event of a job change or layoff. It sounds a lot like some of the "national health care" proposals being debated in Congress in recent years, but with one twist: It's a private company offering it, and a private company that will reap any profits to be gained from the savings.

And one more twist: It gives small businesses one more reason to become customers of Sam's Club, rather than of rivals Costco and BJ's (NYSE:BJ).

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Fool contributor Rich Smith has no position in any of the companies mentioned in this article.