Finnish telecom giant Nokia (NYSE:NOK) has announced that it intends to nearly double its stake in Symbian, a British software developer for the mobile handset market, by buying Psion PLC's 31% interest in Symbian.

Nokia already owns more than 32% of Symbian, dwarfing all of the individual stakes held by co-owners Siemens (NYSE:SI), Ericsson (NASDAQ:ERICY), Sony Ericsson (a joint venture between Sony (NYSE:SNE) and Ericsson), Panasonic (a subsidiary of Matsushita Electric (NYSE:MC)), and Samsung. But now, Nokia wants more than 50% control.

Why Psion is willing to part with its interest in Symbian seems clear. While the firm has already profited from Symbian's handset royalties, Psion also hoped to profit from an anticipated IPO of Symbian. Now, though, because Psion believes that Symbian's business is maturing, it thinks that this maturation will delay Symbian's IPO -- and Psion's subsequent payday.

Nokia's offer to buy the stake allows Psion to make an immediate and certain profit on its initial investment. It also gives Psion the ability to reap continued profits from any royalties that Symbian collects over the next two years (as part of the payment terms of the deal). Lastly, it guarantees that, if Psion jumped the gun and Symbian actually does go public before 2006, Nokia will pay it any difference between the price agreed with Nokia and the value of Psion's stake later sold at the IPO.

What Nokia gets out of the deal, however, is less clear. Nokia agrees to give up certain benefits of ownership to Psion under this deal. And while Nokia may obtain control of Symbian, it also may not.

You see, Symbian's corporate bylaws grant existing shareholders a preemptive right to purchase shares of any exiting shareholder, in proportion to the buyer's existing stake in Symbian. In layman's terms, if Nokia's co-owners of Symbian want to prevent it from acquiring control, they can. In theory, they can limit Nokia to as little as a 46.7% stake -- not the 63.3% controlling stake that Nokia is counting on.

That would deprive Nokia of control over how Symbian counters Microsoft's (NASDAQ:MSFT) move into the mobile handset software market -- Nokia's obvious objective in making its bid. Though Nokia would pay a smaller price for the resulting smaller stake, if its main objective is thwarted, it might just decide to abort the deal.

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Rich Smith is a Motley Fool contributor. He owns no shares in any company mentioned in this article, although he has owned shares of Nokia in the past. The Fool has a disclosure policy .