Lenovo is rumored to be pondering a bid for BlackBerry, a possibility that could lead to some major indigestion considering the PC maker is about to close the purchase of Motorola Mobility. But the concept does raise the question about whether a multi-brand effort can work in the smartphone market.

According to Benzinga, a financial news site, Lenovo could make an offer as early as this week. Other news outlets picked up on the report since BlackBerry shares were moving on the rumor.

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I'd argue that Lenovo buying BlackBerry this soon is a stretch. First, there are regulatory issues. In addition, BlackBerry finally has some momentum and it's doubtful it would sell out with the launch of the latest BlackBerry Enterprise Server, the linchpin of its turnaround plan, on deck November 13.

Now a Lenovo takeover of BlackBerry may make sense just not at this moment. Lenovo is integrating IBM's x86 server business and Motorola Mobility soon. Google executives said they expect the Lenovo takeover of Motorola to be completed shortly.

Should Lenovo buy BlackBerry it would become the Acer of smartphones. Acer acquired Gateway and Packard Bell to create a group of brands to hit various market segments. Ultimately, Acer remained the alpha brand and the one people know best today. The multibrand strategy worked somewhat for Acer, but wasn't a home run.

Fast forward to Lenovo and the smartphone play. Lenovo would have its own smartphones, which do well in China, Motorola, which does ok in the US and is stronger around the world, and BlackBerry, a enterprise-focused vendor. Lenovo would have to keep all three of those brands and complicate its management strategy.

There's an argument that BlackBerry would give Lenovo a solid enterprise stack — servers, PCs, smartphones and the software and security to manage it all — but a purchase right now looks a bit unwieldy.

Stranger things have happened in technology and BlackBerry looks like it would be a great asset to be acquired. But all these rumors get stopped by the simple question for both sides of the deal: Why now?

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