Cost-Plus Contract

A cost-plus contract pays the contractor for every allowable cost actually incurred during performance and adds either a fixed fee or a percentage of costs as profit, meaning the buyer rather than the contractor absorbs the risk of the work costing more than anticipated.

What is a Cost-Plus Contract?

In a cost-plus arrangement, the contract specifies which categories of cost are reimbursable (labour, materials, subcontracts, equipment hire, overhead at an agreed rate) and how the contractor's fee is calculated. The fee may be a fixed dollar amount, a percentage of actual costs, or an incentive fee that increases if costs stay below a target. Because the buyer pays actual costs, the contractor faces limited financial risk from cost uncertainty, which makes cost-plus appropriate for research and development, emergency response, and highly complex projects where no contractor can reliably estimate a lump sum price.

Cost-plus contracts are closely related to cost-reimbursable-contract arrangements, which is effectively the same concept described under different terminology used by different buyers. Both contrast sharply with lump-sum-contract and fixed-price-contract structures where the contractor holds cost risk. Development banks use cost-plus variants sparingly, generally for emergency works or complex technical assistance where scope uncertainty is extreme; Gulf state-owned enterprises and NATO also apply cost-plus structures to certain research, defence, and early-phase development contracts.

Audit rights are a defining feature: because the buyer pays actual costs, the contract gives the buyer the right to inspect the contractor's cost records, timesheets, and purchasing invoices.

Why Cost-Plus Contracts matter for bidders

Winning a cost-plus contract requires demonstrating that your cost-management systems and accounting practices meet the buyer's audit requirements. Buyers selecting contractors for cost-plus work focus heavily on the contractor's financial controls and track record of keeping costs accurate, because the buyer carries the budget risk. Suppliers must maintain clear separation between reimbursable project costs and their own overhead, and must understand what the contract defines as allowable versus unallowable costs, since billing unallowable costs is a compliance violation.

FAQ

What is the difference between a cost-plus-fixed-fee and a cost-plus-percentage-fee contract?

A cost-plus-fixed-fee contract pays a set profit amount regardless of total costs, giving the contractor no incentive to inflate costs. A cost-plus-percentage-fee contract pays a proportion of actual costs, which can incentivise over-spending and is therefore less common in public procurement.

When do MDBs use cost-plus contracts?

Development banks use cost-plus contracting sparingly, mainly for emergency works, post-disaster reconstruction, or complex technical assistance assignments where defining a lump sum before work begins would be unrealistic.

Why are audit rights important in cost-plus contracts?

Because the buyer reimburses actual costs, they need the right to verify invoices, timesheets, and subcontract costs to confirm that claimed amounts are accurate and allowable under the contract.