If a gift is of community property, it is considered made one-half by each spouse. For example, a gift of $100,000 of community property is considered a gift of $50,000 made by each spouse, and each spouse must file a gift tax return.
Community property is made up of assets that come into marriage during the marriage through any means other than inheritance or gift. Assets acquired by the husband or wife, regardless of how those assets are titled are viewed as assets of the marital community. Not all states recognize community property.
https://www.irs.gov/instructions/i709