A U.S. national security panel is expected to be flooded with additional notifications of cross-border deals as a new law requires more disclosures regarding transactions between U.S. businesses and foreign investors.

Companies also will be required to pay new filing fees, which are aimed at helping the panel with its growing workload. The fees aren’t expected to hurt M&A activity because they’re capped at $300,000, a sliver of the value of most deals.

The changes are part of an annual...