In which of the following contract types does the buyer have the most cost risk?

CPPC contracts reimburse the contractor for all allowable costs and pay an additional fee calculated as a percentage of those costs. This structure means the contractor actually earns more as costs rise, creating a perverse incentive. The buyer absorbs unlimited cost growth with no contractual mechanism to control it, making CPPC the riskiest contract type for the buyer.

CPFF reimburses costs plus a fixed fee that does not change regardless of actual costs, giving the contractor some incentive to control costs and limiting fee exposure for the buyer.

CPAF reimburses costs plus an award fee determined by buyer-assessed performance, which provides a performance incentive that partially protects the buyer.

CPIF reimburses costs plus an incentive fee tied to meeting target cost goals, which motivates the contractor to control costs and shares savings between both parties.