Your corporation (and you if you hold yourself as the car's owner, aand your business partner co-shareholder, if you and he commingle corporate assets like this) need to get a written release from your friend for any liablity from this accident.
As my colleague pointed out, this is how you lose your corporate shield and get its "veil pierced," holding you personally responsibile for liabilities, because you're not repsecting the corporate's distinct ownership by lending its assets to your friend.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
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