Close partners GM and Lyft were apparently nearly even closer: The Information reports and TechCrunch has separately confirmed that the carmaker expressed its interest in purchasing Lyft, going so far as to specify a price it would’ve been wiling to pay. Lyft apparently explored what other strategic partners might be offering before deciding to say no to GM and opt instead to raise new funding.

Lyft declined to comment to TechCrunch on the report, but a source close to the matter confirms that the on-demand service provider turned down GM. GM also declined to comment on any acquisition reports, but noted that they were extremely pleased with how the strategic partnership with Lyft was going.

The Information’s info suggests that GM’s interest in the car sharing market extends beyond simply partnering up with an external party. Other carmakers like Daimler have opted to own their own car sharing subsidiaries, with the German automaker operating Car2Go, and commanding a controlling stake in the merged Hailo/MyTaxi European on-demand ride provider.

In statements to The Information, both companies expressed continued excitement and enthusiasm about their ongoing partnership. Most recently, this partnership has resulted in the expansion of their Express Drive program, which offers potential Lyft drivers without their own qualifying cars the ability to rent vehicles to use for Lyft with fees based on usage.

Lyft and GM also plan to test self-driving taxis, with autonomous systems installed in all-electric Chevy Bolt vehicles. Self-driving Bolt tests using tech provided by GM acquisition Cruise have already begun in SF and Arizona.

Depending on the size of the offer on the table, this could prove a risky move by Lyft. It already faces steep competition from Uber, which has far more cash on hand thanks to a series of monster equity and debt raises. Meanwhile GM could decide it wants to own its own operation, and either look around for another acquisition target like Daimler, or build an in-house on-demand ride service, which is what Ford appears to be doing with its Smart Mobility subsidiary.

Of course, the fact that GM made overtures and Lyft decided to pass this time around doesn’t forego future merger potential. But it does make watching the partnership’s progress far more interesting from here on out.