Brand theory might suggest that the smart play is for a company to focus all of its energy on a single brand. But there’s a time and place to branch out…and a right way and wrong way. Industry brainiacs Al & Laura Ries even devote an entire chapter to this idea in their book “The 22 Immutable Laws of Branding.” They call it “The Law of Siblings.”

There is rarely anything so absolute as an immutable law in the world of branding. But this one comes close.

The danger of launching a second brand is that if you handle it incorrectly, the second brand will dilute the first brand and waste your valuable resources. When Anheuser-Busch launched Bud Select, it grabbed a 1.3% market share. In the same period of time, all other Anheuser-Busch brands lost just over 1% market share, leading industry experts to suggest that Bud Select was eating its own.

It makes sense when you think about it. Does Bud Select not imply that regular Bud isn’t quite as good? Who wants regular when they can have Select? In the same manner, doesn’t Hellmann’s Light imply that regular Hellmann’s is fattening and unhealthy? Doesn’t Extra-Strength Tylenol suggest that regular Tylenol isn’t strong enough?

Years ago, Coca-Cola launched Tab to combat Diet Pepsi. Tab dominated the diet cola market, leading by nearly 1/3. Then Coke got greedy, dropped Tab, and launched Diet Coke to replace it. Diet Coke was soundly spanked by Diet Pepsi. Not only that, but Coca-Cola as a whole lost market share. This move took nearly two decades to correct.

Why did that happen? Because Diet Coke implied that Coke Classic wasn’t good for the figure. So Coke Classic drinkers switched to Diet Coke while Pepsi drinkers drank Diet Pepsi.

So, clearly, tapping into the success of one brand to launch a sibling is not a winning strategy. It rarely works.

How should a business launch a second brand? First and foremost, you should always make each sibling a unique and individual brand name. Resist the temptation to give the siblings a family look or identity. It won’t work. Instead, make them as unique and distinct as possible. Here are some examples:

• Wrigley’s siblings Big Red, Winterfresh, Altoids, and Orbit all can stand on their own as unique, individual brands.
• Red Lobster was once the largest family restaurant chain in the US. It’s owned by General Mills. When General Mills got the urge to launch an Italian restaurant chain, it did so with a completely different name and identity: Olive Garden.
• When Sara Lee launched a line of panty hose, it didn’t rely on the super-successful Hanes brand. Instead, it launched Leggs.
• When Black & Decker shifted from consumer to professional power tools, it didn’t stick with the Black & Decker name. It launched Dewalt.
• When Honda wanted an expensive car, it didn’t launch Honda Plus, it created Acura.
• Toyota did the same with Lexus.

All of the above examples were hugely successful. They were successful because they launched a sibling brand the right way, and by sticking to a few practical points of strategy:

1. Focus on a common product area such as passenger cars, chewing gum, headache medicine, etc.
2. Select a single attribute to segment. Price is the most common, but others include distribution, age, sex, flavors, etc. This will help minimize confusion between siblings.
3. Setup rigid distinction between brands. Again, price is the easiest, but other methods might include target demographic, creative concept, attitude, personality, etc.
4. Create different, not similar brand names. Again, names that are too similar will too closely associate your siblings and create unnecessary and potentially harmful competition. Be diverse. Very diverse.
5. Launch a new sibling only when you can create a category. Siblings should not be launched just to fill a hole in an existing line or to compete with another brand. Coca-Cola launched Mr. Pibb to block Dr. Pepper, Fruitopia to block Snapple, and Mello Yello and Surge to block Mountain Dew. None of them worked.
6. Keep control of sibling brands at the highest level. Avoid sibling rivalry.

In short, launching a sibling brand can work. But it must be done with care, and it must be done with the above guideposts in mind. Otherwise, you’ll wind up with siblings eating their own.

And that might leave a pretty sour aftertaste.