What is the maximum holding speed when cleared to enter a published hold at 16,000'?

When entering a published hold at an altitude of 16,000 feet, the maximum holding speed is 265 knots indicated airspeed (KIAS). This speed is determined by regulations outlined in the Aeronautical Information Manual (AIM) and other governing flight standards, which specify that for altitudes between 14,001 feet and 20,000 feet, the maximum holding speed is 265 KIAS.

This speed limit ensures safe maneuverability and compliance with the aircraft's structural and operational limits while in a holding pattern, which typically involves changes in direction and altitude. By adhering to this speed, pilots can maintain control of the aircraft and ensure safety during the holding process. Other speeds presented in the question either exceed the regulatory limits or apply to different altitude categories, making 265 KIAS the correct and safe choice for this scenario.