The rule exists to stop “bid shopping” and “bid peddling,” where a prime shops a sub's number around after award to squeeze out a lower price. In California, the Subletting and Subcontracting Fair Practices Act requires listing each sub (with license number) performing more than one-half of one percent of the bid, and bars substitution after award except for narrow statutory reasons. Listing the wrong sub — or none — can trigger penalties or a nonresponsive bid.
The Act also treats certain prime mistakes carefully: failing to list a sub for a portion of work over the threshold can be read as the prime committing to self-perform that scope. Permitted substitutions are limited to specific situations — a listed sub that refuses to sign, becomes insolvent, or can't furnish required bonds — and usually require written notice and the agency's consent. Nonlinear supports subcontractor coordination by generating scope-based sub lists and distributing bid invitations, helping primes line up and accurately list the trades they're required to name.

