It’s fairly simple for a member or manager to sign a legal document as a representative of a Limited Liability Company that properly identifies the company as a party to the agreement rather than the person signing. Unfortunately, it’s also fairly simple to screw it up. If a person’s not careful, he could end up personally liable for any debt incurred from an agreement he signed, which the LLC was specifically designed to protect against.
The key to a proper signature is to make it clear who the person is signing for. If the signature is just Jane Jones, the implication is that Jane Jones is the liable party. To avoid that, the signature should make Jones’ role clear. If she is one of the owners of the company, she is called a member, and can sign a document as:
Jane Jones Great Stuff LLC A Michigan Limited Liability Company By: (signature) Member
If the LLC members give the authority to a hired manager to sign for the company, the signature format is the same except the title is Manager instead of Member. Use the same format for signing any document on behalf of the company, including deeds, contracts, court filings and letters of agreement.
Even if an LLC member is careful to follow the proper format for a signature, language in a contract or other agreement can remove the member’s liability protection. A service agreement that begins as an “an agreement between XYZ Services and John Smith, an individual doing business as Great Stuff LLC” could have a court find in any future dispute that both John Smith and the LLC are liable for any debt or damages incurred. A "doing business as" signature identifies the person and the company as a single legal entity.
If a member’s personal name is included in the body of the agreement, and the language doesn’t make clear the person is only acting on behalf of the company, require the name to be removed. Do not accept any assurances from the other party that the language wasn’t intended to create a personal liability, because that may not be how a judge sees it if a dispute winds up in her court.
Any LLC member can sign a company check or endorse a check made to the company as long as the signature is on file with the bank. The same is true of a hired manager. The members, however, can decide to include in the LLC’s operating agreement who is responsible for signing and endorsing checks, and even require two signatures on company checks if they feel the need for extra security.