I am seeking best practices for private company Executive Committees. In particular, how often should they meet, what authority should they possess, and thoughts about whether they are needed. 

Weekly short meeting (business is changing so fast), and monthly longer meeting. "offsite" strategy days quarterly. 

The frequency of EC meetings depends on the company’s size and complexity. Monthly or quarterly meetings are common. Their authority should align with strategic decision-making, while day-to-day operations are typically handled by the CEO.

Whether they’re needed depends on the company’s structure and challenges; some find value in streamlined decision-making, while others rely on a more decentralized approach. It’s crucial for compliance professionals especially to tailor practices to the company’s unique needs and context. Policymaking and policy development in this regard is critical by an organization’s Legal/Compliance team.