12.2 Group Underwriting and Contribution/Participation

Key Takeaways

  • Contributory plans require employees to share in the premium and generally require 75% participation of eligible employees.
  • Noncontributory plans are fully employer-paid and require 100% participation of eligible employees.
  • Higher participation requirements exist to prevent adverse selection.
  • Experience rating sets a group's premium from its own claims history; community rating uses a regional average.
  • Credibility weights how much of the group's own experience is used versus the manual rate.
Last updated: June 2026

Once a group is eligible, the insurer must decide how it is paid for and how it is priced. The exam heavily tests participation percentages, because they are the primary defense against adverse selection within a group.

Contributory vs. Noncontributory Plans

Plan typeWho pays premiumRequired participation
NoncontributoryEmployer pays 100%100% of eligible employees must be covered
ContributoryEmployee shares the costUsually 75% of eligible employees must enroll

The logic: if employees pay nothing (noncontributory), everyone should be enrolled, so the insurer demands 100%. When employees must pay part of the premium (contributory), some will decline, so the insurer accepts a 75% floor but no lower.

Why Participation Matters

Participation requirements stop adverse selection—the tendency for sicker people to be the most eager to enroll. If only the unhealthy join, claims spike and the pool collapses. Requiring 75% (contributory) or 100% (noncontributory) forces healthy members into the pool, balancing the risk.

Trap: A common wrong answer reverses the figures. Memorize: noncontributory = 100%, contributory = 75%.

Employer Contribution Rules

  • Employer contributions toward group health are generally tax-deductible as a business expense.
  • Employee-paid premiums may be made pre-tax through a Section 125 cafeteria plan (covered in 12.4).
  • Group medical benefits received by an employee are generally not taxable income to the employee.

Group Rating Methods

The insurer prices the group using either community rating or experience rating.

MethodBasisTypical use
Community ratingAverage cost of all groups in a regionSmall groups; ACA individual/small-group market
Experience ratingThe specific group's own claims historyMedium and large groups
Manual (tabular) ratingStandard rate tables by classStarting point before adjustment

Experience Rating and Credibility

For larger groups the insurer blends the group's own claims with the manual rate. Credibility measures how statistically reliable the group's own experience is—larger groups get higher credibility.

Group Premium = (Credibility x Group's Own Claims Rate)
              + ((1 - Credibility) x Manual Rate)

Worked example: A 400-life group is assigned 70% credibility. Its own experience indicates a rate of $500 per member; the manual rate is $600.

Group Premium = (0.70 x $500) + (0.30 x $600) = $350 + $180 = $530 per member.

The more lives in the group, the closer credibility moves toward 100% and the more the group's own experience drives the price.

Underwriting the Group Itself

Even though individuals are not medically underwritten, the group is. The underwriter evaluates characteristics that predict the group's expected claims and stability.

Group factorWhy it matters
Industry/occupationHazardous occupations raise expected claims
Group sizeLarger groups are more statistically predictable
Age and gender mixOlder or higher-risk demographics raise costs
Geographic locationRegional medical-cost differences
Prior claims (loss) experienceIndicates future cost; basis for experience rating
Stability/turnoverHigh turnover invites adverse selection

The underwriter also confirms the group meets the persistency and minimum-size rules. A group that has existed only to buy insurance, or that is shrinking rapidly, is a poor risk because the healthy members may leave first, leaving a sicker residual pool.

Trend, Loss Ratio, and Renewal

At renewal, the insurer re-rates the group using its emerging experience and a trend factor (expected medical inflation). A key metric is the loss ratio—claims divided by premium.

Loss Ratio = Incurred Claims / Earned Premium

Worked example: A group pays $1,000,000 in annual premium and generates $850,000 in incurred claims. Its loss ratio is $850,000 / $1,000,000 = 85%. If the insurer targets a 75% loss ratio, the group is running unprofitably, and the renewal premium will rise (subject to credibility) to bring the expected ratio back toward target. A group consistently below target may earn a rate reduction.

Probationary Periods and Minimum Group Size

Group health underwriting also relies on structural safeguards that the exam tests directly. A minimum group size (often two or more for small-group rules, larger for full experience rating) ensures the law of large numbers applies. A probationary period for new hires defers coverage long enough to discourage someone from taking a job purely to obtain immediate treatment.

SafeguardEffect on adverse selection
Minimum participation (75%/100%)Keeps healthy lives in the pool
Minimum group sizeMakes claims statistically predictable
Probationary/waiting periodDeters insurance-motivated hiring
Active-work requirementConfirms the member is a true working employee

Together these rules let the insurer waive individual medical underwriting while still controlling the overall risk. When a group fails to meet participation after issue—say enrollment slips below 75% on a contributory plan—the insurer may re-rate or non-renew, because the protective balance has broken down.

Contributory Versus Noncontributory Participation Rules

The most-tested group-underwriting numbers concern participation. In a noncontributory plan the employer pays the entire premium, so 100% of eligible employees must be covered — this eliminates adverse selection because no one self-selects out. In a contributory plan employees share the cost, and insurers historically require at least 75% participation of eligible employees to issue the group.

The logic is that high participation dilutes the impact of a few high-claim members. Worked example: an employer with 100 eligible employees on a contributory plan generally needs at least 75 to enroll for the carrier to offer group rates and forgo individual medical underwriting. Group coverage is underwritten on the characteristics of the group as a whole — its size, industry, age and gender mix, and claims experience — not on each member's health.

Test Your Knowledge

A group health plan is fully paid for by the employer. What participation level does the insurer require?

A
B
C
D
Test Your Knowledge

Using a credibility of 60%, group claims rate of $400, and manual rate of $500, the blended group premium per member is:

A
B
C
D