1. The Department of Justice and the Federal Trade Commission are responsible for approving mergers and enforcing antitrust law.

2. Market definition is one of the main parts of current merger guidelines.

3. The Federal Reserve oversees the enforcement of antitrust law.

4. Measure of concentration is one of the main parts of current merger guidelines.

5. Mergers that result in a relatively high HHI are less likely to be approved than mergers resulting in a lower HHI. 6. Firm diversification is one of the main parts of the current merger guidelines.