A more thorough explanation:

The Hart–Scott–Rodino Antitrust Improvement Act is a law passed by the United States government in 1976. It gives the Justice Department more power to enforce antitrust laws, which are designed to prevent companies from becoming too big and dominating the market. The law requires companies to notify the Federal Trade Commission and the Justice Department if they plan to merge with another company and if one of the companies has annual revenues or assets over $100 million and the acquisition price or value of the acquired company is over $15 million.

For example, if Company A wants to merge with Company B and Company A has annual revenues of $150 million and Company B has assets worth $120 million, they would need to notify the government of their plans because one of the companies has annual revenues or assets over $100 million. If the acquisition price or value of Company B is over $15 million, they would also need to notify the government.

This law helps prevent companies from becoming too big and dominating the market, which can lead to higher prices for consumers and less competition. By requiring companies to notify the government of their plans to merge, the government can review the merger and make sure it is not harmful to competition.