California lawmakers passed several laws in recent years to strengthen worker protections in industries where contracting is common, and to help workers collect unpaid wages. 

Contracting allows big firms to escape liability for wage theft, advocates say, because the big firms hire contractors, who directly employ the workers and are often accused of wage theft.

If they were jointly liable, then the larger firms would be legally on the hook for any unpaid wages along with their contractors and subcontractors.