In the construction world, managing risk is critical. Two common tools used to protect against the risk of subcontractor failure are Subcontractor Default Insurance (SDI) and Surety Bonds. While they both aim to protect the general contractor and project, they work in very different ways and benefit different parties.
This article explains the key differences between the two, and helps contractors, subcontractors, and project owners understand who gains what from each approach.
What Is a Surety Bond?
A surety bond is a three-party agreement between the subcontractor (principal), the surety company, and the project owner or general contractor (obligee). It guarantees that the subcontractor will fulfill its contractual obligations.
If a subcontractor defaults, the surety may:
• Finance the subcontractor to complete the work
• Hire a replacement contractor
• Pay the bond penalty amount
If the surety pays a claim, it will seek reimbursement from the subcontractor through the indemnity agreement.
Surety bonds are especially common on public construction projects, where they are often required by law. They provide a direct benefit to the project owner and shift much of the risk evaluation and response to the surety.
What Is Subcontractor Default Insurance (SDI)?
Subcontractor Default Insurance is an insurance policy purchased by a general contractor. It protects the GC against financial losses if a subcontractor fails to perform.
Unlike a surety bond, SDI does not involve a third-party stepping in to manage the default. The general contractor controls the response. The GC can:
• Declare the subcontractor in default
• Replace the subcontractor quickly
• Repair defective work
• Submit a claim to recover both direct and certain indirect costs, such as delay expenses and overhead
SDI is written for the direct benefit of the general contractor. Project owners may benefit indirectly because issues can often be resolved more quickly.
There are typically two types of SDI buyers:
1. Large general contractors that enroll all projects into a multi-year rolling SDI program. These contractors take on full responsibility for subcontractor prequalification and usually retain larger deductibles and co-insurance obligations.
2. Mid-sized or smaller general contractors that use per-project SDI programs. Some carriers in this space assist with subcontractor prequalification and may offer percentage-based loss sharing instead of large, fixed deductibles.
Who Benefits from Each?
General Contractors
• Surety Bonds – Ideal for public projects, transfer more risk to the surety, and lower administrative burden on the GC
• SDI – Provides greater control and faster response, broader coverage (including certain indirect costs), and common on large private commercial projects with many subcontractors
SDI offers speed and flexibility, but it also requires strong subcontractor prequalification and internal risk management.
Subcontractors
• Surety Bonds – Demonstrate financial strength, provide a structured claims process, and help protect legal rights in disputes
• SDI – Offers no direct protection to the subcontractor, allows the GC more discretion in declaring default, and can increase risk exposure for the sub
Under SDI, the policy protects the general contractor, not the subcontractor.
Project Owners
• Surety Bonds – Standard on public jobs, provide legal and financial protections, and offer recourse through the surety
• SDI – No direct contractual protection unless required by the contract and indirect benefit through faster replacement of non-performing contractors
Choosing Between SDI and Surety Bonds
The right solution often depends on project type, risk tolerance, and administrative capacity.
Public infrastructure projects
Surety bonds are typically required.
Large private commercial projects with many subcontractors
SDI can provide speed and flexibility.
Owners seeking layered protection
A combination of bonds and SDI may be appropriate.
GCs seeking lower administrative burden
Surety bonds may be a better fit.
GCs seeking more control and faster decision-making
SDI may align better with that strategy.
Hybrid Approaches
Many general contractors use a blended strategy. They may rely on SDI for most subcontractors but still require bonds for:
• High-risk trades
• Large mechanical or electrical packages
• Critical path subcontractors
• Financially weaker firms
This approach balances control with traditional risk transfer.
In Conclusion
Both Subcontractor Default Insurance and Surety Bonds help manage subcontractor risk, but they serve different purposes, benefit different parties, and come with different responsibilities.
Understanding the pros and cons of each can help contractors and subcontractors negotiate smarter contracts, protect their interests, and respond quickly when problems arise.
If you would like to learn more about Subcontractor Default Insurance, per-project SDI programs, or a surety program financial assessment, contact or connect with a member of the McConkey Insurance & Benefits team.
