What is the effect of having a "sick pool" on insurance premiums?

A "sick pool" refers to a situation in which a disproportionate number of unhealthy individuals enroll in a particular insurance plan. This brings forth greater overall medical claims against the insurer because the members of the pool tend to incur higher healthcare costs. As a result, the increased risk associated with insuring a higher concentration of sick individuals typically leads to higher premiums. Insurers must account for the elevated costs in their pricing structure to maintain financial viability, which is why having a sick pool often results in higher premiums for all policyholders.

The other options do not hold true in the context of insurance principles. A sick pool would not lead to lower premiums since the inherent risk is higher; it does have a significant impact on premiums, contrary to the notion that it has no impact; and it does not stabilize premiums but rather causes variability based on the health profiles of the insured individuals.