What is the most common method of perfecting a security interest under article 9?

The most common method of perfecting a security interest under Article 9 of the Uniform Commercial Code (UCC) is by filing a financing statement, typically known as a UCC-1 form, with the appropriate state authority. This public filing provides notice to third parties of the secured party's interest in the collateral. Other methods of perfection include possession of the collateral or control, depending on the type of collateral involved.