California's largest business and labor groups agreed to change a landmark law that has helped workers sue companies such as Walmart Inc., Uber Technologies Inc. and Google for workplace violations.

The deal caps years of efforts by the state's employers to rein in the Private Attorneys General Act, which they blame for mounting lawsuits that according to one study have cost businesses $10 billion during the past decade. Advocates say the law, known as PAGA, is a model of worker protection that has given employees a measure of recourse against powerful companies.