So let me get this straight: First, Toyota (NYSE: TM) invites Tesla (Nasdaq: TSLA) to its old NUMMI factory in California, and invests $50 million in the electric car pioneer. Then, it hires Tesla to build it an electric RAV4. Now, it appears Toyota is introducing Tesla to all its friends, and playing matchmaker with the upstart. It gets a Fool to wondering: Will Toyota marry Tesla itself?

On Wednesday, Panasonic (NYSE: PC) announced it's joining Toyota in making equity investments in Tesla. It's $30 million, to be precise, enough cash to snap up an introductory 2% stake in the electric operator. Panasonic, as you are probably aware, is the company that builds battery packs for Toyotas including the Prius gas-electric hybrid (and for Ford (NYSE: F) and Honda (NYSE: HMC) hybrids, as well). What you may not be aware of is the fact that Panasonic also makes Tesla's batteries.

This being the case, a Fool can wonder: Why did yesterday's news send Panasonic shares up 3.7%? I mean, it's not as if Panasonic secured a new customer by buying into Tesla. It already "had 'em at konnichiwa."

And an even more curious development: Tesla shares popped more than 14% on the news, ending the day just shy of $25. This despite the fact that Panasonic clearly stated it's only paying $21.15 apiece for its stake. I can hear Tesla investors now: "What? I have a chance to buy shares for a mere 18% markup over what somebody else paid for them yesterday? Sign me up!"

Where's the bargain?
Call me crazy, but that just doesn't sound like a great deal to me. Fools, the plain fact of the matter is that nothing has really changed here. Tesla had a good source of batteries before; it still does. Panasonic had a happy customer; and it still does.

As for Toyota, I'm sure it's happy to see its two friends getting along so well, and maybe we're seeing another example of the Japanese concept of keiretsu -- but in practice, the concept rarely works as advertised. What's more, the longer these folks run around buying bits and pieces of each other's companies, the less likely it becomes that anyone's going to upset the apple cart and just out-and-out buy Tesla at a premium.

Or am I missing something? Do you see a good reason for Panasonic's buy-in driving Tesla shares up 14%? For Panasonic's own 4% bump? Tell us about it below.

Ford Motor is a Motley Fool Stock Advisor pick, but Fool contributor Rich Smith does not own shares of any company named above. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Fool has a disclosure policy.