A $50 million development can quickly become a $60 million problem when construction costs spiral. Guaranteed Maximum Price contracts are designed to give developers greater budget certainty—but the protection depends on what the agreement actually says.

A developer can spend years assembling land, securing zoning, arranging financing, and designing a commercial building. But unexpected foundation issues, electrical equipment price increases, subcontractor failures and design revisions can change the economics once construction starts.

The central question for developers, investors and lenders is who pays when construction costs exceed the original budget. One tool is the Guaranteed Maximum Price (GMP) contract, which establishes a maximum amount the owner pays for defined construction work, subject to authorized adjustments.

A GMP does not guarantee an entire development budget, eliminate change orders, prevent delays or transfer every risk to the contractor.

What Is a Guaranteed Maximum Price Contract?

A GMP sets a negotiated ceiling on what a contractor can charge for a defined construction scope. It commonly uses cost-plus pricing: the owner reimburses allowable actual costs plus an agreed fee, up to the contractual maximum.

When qualifying costs exceed the ceiling without an authorized adjustment, the contractor generally bears the excess. If costs come in below the maximum, the owner may benefit from the savings, subject to any negotiated sharing arrangement.

AIA Document A133–2019 is a widely used example for a construction manager serving as adviser and constructor. The manager may provide preconstruction advice, submit a GMP proposal and enter a GMP amendment once the owner accepts the proposal.

The key concept is a ceiling for agreed work—not an immutable limit on every event that might occur during the project.

Inside a $50 Million GMP Construction Budget

Consider a hypothetical Charlotte mixed-use development with apartments, ground-floor retail and parking. Its negotiated $50 million GMP includes site preparation and foundations ($5 million), structural work ($12 million), mechanical, electrical and plumbing ($11 million), envelope and roofing ($5 million), interiors ($9 million), general conditions ($3 million), contractor contingency ($2 million) and fee ($3 million).

These allocations are illustrative rather than market bids. At completion, if allowable costs and fee total $47 million, savings of $3 million may be retained by the owner or shared with the contractor under the agreement.

If qualifying costs instead total $53 million and there is no authorized adjustment, the contractor generally absorbs the $3 million overrun within its assumed risk. But if the developer approves additional amenities requiring $2 million and a change order increases the maximum, the GMP may become $52 million.

The maximum applies to the defined scope and approved risk allocation. Owner-directed changes and certain other contractually specified events can alter it.

Why Developers Use GMP Contracts

A negotiated ceiling can make budget planning more predictable and help lenders and investors evaluate a project’s funding needs.

GMP arrangements often involve contractors during preconstruction, when they can advise on scope, materials, constructability, procurement and schedule before design decisions become expensive to change.

Cost-plus compensation can also create greater visibility into expenditures, provided the contract defines reimbursable costs, reporting requirements, supporting records and owner audit rights.

For owners, the benefit is not a magic fixed number but a clearer system for managing construction risks and responsibilities.

A GMP Is Not an Unlimited Guarantee

A GMP may be adjusted for owner-directed changes, specified concealed conditions, changes in law, certain delays or other negotiated events. Which party carries the risk depends on the contract.

One contractor may include most trade and procurement costs but exclude certain utility connections or equipment. Another may submit a higher figure with fewer qualifications. The proposals cannot be evaluated fairly without reviewing scope, assumptions and exclusions.

A $48 million GMP riddled with exclusions can create more owner exposure than a more complete $50 million proposal.

Contractor Contingency vs. Owner Contingency

A contractor contingency within the GMP may be available for defined uncertainties, including limited scope gaps or coordination problems. The agreement should identify who controls its use, what documentation is needed and what happens to unused funds.

A separate owner contingency typically sits outside the GMP to help fund owner-driven changes or risks the owner retains. For instance, a $50 million GMP could be one component of a larger development budget with an additional $3 million owner reserve.

The owner reserve is not automatically the contractor’s money; its application depends on the contract and development budget.

How Contractors Calculate a Guaranteed Maximum Price

The contractor first evaluates drawings, specifications, site reports and scope. It then seeks subcontractor and supplier pricing for structural, electrical, mechanical, façade and other trade work.

The estimate adds general conditions for supervision, site administration, temporary facilities and safety, followed by agreed allowances, contingencies and fees. The contractor identifies assumptions and exclusions before presenting the proposed maximum.

If the owner asks for a GMP when major drawings remain unfinished, the contractor may price more uncertainty into its contingency or rely on broader exclusions. A deceptively low early estimate can lead to conflict if the design is not sufficiently defined.

GMP vs. Lump Sum vs. Cost Plus

A GMP generally reimburses eligible actual costs plus a fee up to an agreed maximum, subject to authorized changes. A lump-sum contract establishes a stipulated price for defined work, again subject to contract adjustments.

Cost-plus without a GMP provides flexibility but leaves the owner more exposed to allowable cost increases. Unit-price contracting uses measured quantities and agreed rates and can be appropriate when final quantities are uncertain.

No model is automatically best. A straightforward warehouse with complete drawings may suit lump sum; a complex mixed-use project may benefit from early builder involvement and a GMP; uncertain excavation quantities may call for unit pricing on selected work.

Miami: Controlling High-Rise Construction Risks

High-rise developments in Brickell and other dense Miami neighborhoods can face complex foundations, groundwater, urban staging, façade procurement and mechanical-system requirements.

A GMP can establish a clearer price framework, but the parties must decide which subsurface conditions, engineering requirements, material escalation events and delay risks are included.

A well-defined scope and detailed site investigations are central to making that ceiling credible.

Charlotte: Managing Development-Corridor Costs

Charlotte projects can involve structured parking, utility connections, urban logistics and infrastructure improvements on emerging development sites.

Early contractor input can help establish a realistic GMP before lenders and investors commit capital. The contract must distinguish contractor work from owner-controlled approvals, off-site improvements and design changes.

Nashville: Procurement and Scheduling Risks

Major construction and infrastructure projects can compete for specialty trades and long-lead equipment. Procurement planning therefore affects project risk as much as base pricing.

A GMP does not automatically make a contractor responsible for every delivery delay. Contract provisions determine extensions, compensation and remedies, while documentation can establish how an event affects the critical path.

The Cost of Time Is Not Always Covered

Even when construction costs remain within the GMP, delayed occupancy can postpone rent, increase interest carry and trigger lender requirements.

Owners may also need milestone dates, substantial completion provisions, extension rules, liquidated damages and practical schedule reporting. A price ceiling is not a substitute for a credible delivery schedule.

The Legal Side of Guaranteed Maximum Price Contracts

Construction counsel reviews the defined drawings and scope; allowable costs; contractor fee; contingencies; change-order and notice provisions; savings-sharing; audit rights; schedule obligations; insurance and bonding; and dispute-resolution procedures.

Standard AIA forms provide a starting framework but are commonly modified for project-specific risks. Two contracts labeled GMP can allocate those risks very differently.

Five Questions Before Signing a GMP

First, is the design sufficiently complete to support a realistic ceiling? Second, which utilities, permits, site work, equipment or other costs are excluded? Third, who controls contractor and owner contingency?

Fourth, exactly which events permit the maximum price to increase? Fifth, does the contractor have the staffing, financial capacity, insurance, bonding and operational systems to deliver within the agreed scope?

The answers often matter more than a seemingly attractive headline number.

Is a GMP Always the Best Option?

Not necessarily. An owner seeking early cost transparency and constructability support may benefit from a GMP, but substantial design uncertainty can encourage conservative pricing or disputes about exclusions.

For a fully designed, straightforward project, a competitive lump-sum contract may be simpler. The goal should be to allocate risk to the parties best placed to manage it.

The Business Behind the Maximum Price

Developers model rents, financing costs, cap rates and projected returns long before a building is completed. Construction cost overruns can undermine those projections.

For contractors, GMP commitments require disciplined estimating, procurement and trade management. For lenders and investors, they can improve visibility into cost exposure. For attorneys, they establish which party is responsible when reality differs from the original plan.

A Guaranteed Maximum Price does not guarantee that nothing will go wrong. It helps determine who bears specified costs when things do. Its value depends on the contract, the estimate and the team’s ability to perform.

Corporate Rizz covers the construction firms, developers, investors and legal professionals shaping commercial real estate across the Southeast.

Editorial Methodology and Sources

This article is general construction-industry reporting, not legal or financial advice. The $50 million budget and scenarios are illustrative. Actual obligations depend on negotiated contract terms, scope and applicable law.

Research references: American Institute of Architects A133–2019 and Exhibit A, Guaranteed Maximum Price Amendment; AIA A102–2017, cost of the work plus a fee with a GMP; Procore’s July 2026 industry guide to GMP contracts.