California Code, Vehicle Code - VEH § 39006

(a) Each bicycle retailer and each bicycle dealer shall supply to each purchaser a preregistration form provided by the licensing agency and shall include, on the sales check or receipt given to the purchaser, a record of the following information: name of retailer, address of retailer, year and make of the bicycle, serial number of the bicycle if delivered to the purchaser in an assembled state, general description of the bicycle, name of purchaser, and address of purchaser. A copy of the preregistration form shall be filled out and forwarded by the purchaser to the appropriate licensing agency within 10 days from the date of sale.

(b) For the purposes of this division, a bicycle dealer is any person who sells, gives away, buys, or takes in trade for the purpose of resale, more than five bicycles in any one calendar year, whether or not such bicycles are owned by such person. “Bicycle dealer” also includes agents or employees of such person.