Where the company provides guarantee for shareholders and actual controllers, it shall be approved by the shareholders' meeting or shareholders' meeting. The legal representative of the company signed the letter of guarantee without the approval of the resolution of the company's shareholders' meeting, which belongs to the behavior of the legal representative of the company exceeding his authority to enter into a contract. The creditor is well aware of the above control relationship and has not carefully examined the effective internal resolutions of the listed company. It is not a bona fide counterpart, so the letter of guarantee involved is invalid.