California Code, Civil Code - CIV § 8724

(a) The letter of credit shall be issued by a financial institution, as defined in Section 5107 of the Financial Code, inuring to the benefit of the direct contractor.

(b) The letter of credit shall be in an amount not less than 15 percent of the contract price for the work of improvement or, if the work of improvement is to be substantially completed within six months after the commencement of work, not less than 25 percent of the contract price.

(c) The maturity date and other terms of the letter of credit shall be determined by agreement between the owner, the direct contractor, and the financial institution, except that the owner shall maintain the letter of credit in effect until the owner has satisfied its payment obligation to the direct contractor.