Here's why:

* The Sun's Mass: The Sun accounts for over 99% of the total mass of the solar system.

* Angular Momentum Formula: Angular momentum is calculated as the product of mass, velocity, and radius. Since the Sun has the vast majority of the mass, even a relatively slow rotation contributes significantly to the total angular momentum.

* Orbital Momentum: While the planets do have angular momentum from their orbits, the Sun's mass dominates the calculation.

Therefore, even though the planets are moving, the Sun's massive size and relatively slow rotation hold the majority of the solar system's angular momentum.