A new law, Senate Bill 826, is changing the way businesses are run.

This law requires that publicly traded companies headquartered in California have at least one woman on their board of directors by the end of 2019. By the end of 2021, boards with five directors will have to include two women, and boards with six or more directors will have to include three women. Non-compliancy can result in fines as steep as $100,000.

California is the first US state to mandate gender diversity. This law affects businesses of all sizes, as many companies have all male boards.