Apple (AAPL -1.22%) reportedly held talks with BMW (BAMXF -0.19%) about using the frame of its i3 electric car for its own electric vehicle, according to German publication Manager Magazin.

BMW's i3. Source: BMW

Sharing the chassis and running gear, known as "platform sharing," is a common practice among automakers. But if Apple really wants to build a car on BMW's platform, then its auto-making plans could be further along than we previously thought. Back in February, The Wall Street Journal claimed that Apple greenlit a secret electric-car project, known as Project Titan, a year earlier.

Apple hasn't ever acknowledged Project Titan's existence. A BMW spokesman also recently told CNBC that the company regularly meets with Apple, but those discussions are mainly focused on "vehicle connectivity topics" instead of "vehicle development and production."

Would teaming up with BMW make sense?
BMW was notably the first automaker to add iPod support in its vehicles over 10 years ago. More recently, it launched an Apple Watch app, which can monitor an i-Series vehicle's power levels, control the climate, and even open doors.

Plug-in electric vehicle sales accounted for less than 1% of the auto market last year, but it's a rapidly growing market. According to InsideEVs.com, total sales of EVs in the U.S. rose 23% annually last year. The best-selling EV in the U.S. was Nissan's Leaf, followed by General Motors' Chevy Volt, and Tesla Motors' (TSLA -1.92%) Model S.

Tesla's Model S. Source: Tesla

But the BMW i3 gained ground quickly this year. In the first six months of 2015, BMW sold 4,456 i3s in the U.S., putting it in fourth place behind the Model S, Leaf, and Volt -- in that order. The simultaneous rise of the i3 and Model S against the cheaper Leaf and Volt indicates that affluent consumers are fueling the growth of the EV market.

In terms of demographics, there are notable similarities between EV, BMW, and Apple customers. Based on 2013 sales, Experian Automotive found that nearly 21% of EV buyers had an average household income of over $175,000, versus 12% of hybrid buyers. According to 2010 figures, the average BMW owner had a median annual income of $169,000. Last year, comScore reported that the median iPhone app user earns $85,000 per year, compared to $61,000 for the median Android user. Those figures indicate that iPhone buyers might be more inclined to buy BMW EVs.

Why Tesla and Google should watch out
Tesla has made solid progress in the EV market, but it isn't a financial powerhouse. At the end of Tesla's first quarter, it had just $1.5 billion in cash and $2.5 billion in long-term debt. Plenty of people want to buy Tesla's EVs, but the company has struggled to meet that demand with enough shipments.

Apple finished last quarter with over $200 billion in cash, which is enough to buy Tesla six times, based on the latter's current market cap of $33 billion. If Apple gets serious about mass producing EVs, Tesla could be quickly outgunned on the production front and marginalized. That's why some investors previously asked Apple to simply buy Tesla and crack open its production bottleneck.

Google (GOOG -1.10%) (GOOGL -1.23%), which is still experimenting with driverless electric cars, should also watch Apple closely. Apple already locked Google out of connected cars with CarPlay, its dashboard mirroring solution for iPhones. With CarPlay, users are forced to use Apple Maps instead of Google Maps, which prevents Google from gathering data from iPhone users on the move. If Apple only offers CarPlay in its EVs, it could further widen that gap between iOS and Android users in connected vehicles.

Apple's CarPlay. Source: Apple

Let's not get carried away yet
Apple might launch an EV one day, but investors shouldn't get carried away with rumors about "i3 iCars." A Bloomberg report claims that even if those reports are true, Apple probably won't start vehicle production until 2020. For now, investors who are interested in the link between Apple and automakers should focus more on CarPlay, which could seriously hamper Google's ability to track drivers with iPhones.