Lyft's slumping stock price cost General Motors $214 million last quarter

• General Motors' third-quarter financials were adversely impacted by Lyft's struggling stock price.
• The stock's 28% rout during the three-month period cost GM $0.15 per share, or roughly $214 million.
• Despite the slump, GM's investment, originally made in 2016 for self-driving innovation, is likely still in the green.
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Lyft's terrible performance as a publicly traded company had a massive impact on General Motors' balance sheet in the third quarter, the automaker said Tuesday.

The ride-hailing giant's 42% rout since going public in March - 28% of which occurred in the most recent reporting period - cost GM $0.15 per share, or a total of roughly $214 million, based on the current number of shares outstanding. GM owns 6.6% of Lyft.

GM's shrinking stake‚ which was also affected by a drawdown in its partnership with PSA, doesn't necessarily mean that the bet is underwater quite yet. The original $500 million investment was made in January 2016 as part of Lyft's series F funding round. At current prices, that stake appears to be worth about $829 million, according to Bloomberg data.

The investment was touted as a partnership to further self-driving technology advances for both companies.

"We've seen our business changing and the mobility business changing more in the last 5 years than it did in the 50 years prior," GM president Dan Ammann told Business Insider at the time. "We want to lead that change and this [partnership] is an important step along the way."

In the almost four years since, both companies have made notable progress when it comes to autonomy. Lyft, which now offers the ability to hail Waymo self-driving vans in Phoenix, has provided "well over" 50,000 self-driving rides in Las Vegas through its partnership with Aptiv.

"The first generation of autonomous vehicles will only be able to do a small percentage of trips," chief executive Logan Green said in August. "And they'll be critical that they're rolled out on a platform such as Lyft, so that the rest of the rides that are unable to be served by an autonomous vehicle, can be fulfilled by a driver."

Lyft is scheduled to report its own third-quarter earnings on Wednesday, ahead of which executives have said the company expects to become profitable sooner than expected. The company is also hosting a panel of its self-driving leadership next month in California to give progress updates.