What it means
A performance bond is a three-party arrangement between the customer who wants protection, the contractor who buys the bond, and the surety that stands behind it. If the contractor defaults, the surety must either arrange completion or pay the customer, up to a stated maximum known as the penal sum.
It is bought before work starts and usually released on practical completion. It matters because on large construction, engineering and government contracts the cost of a contractor collapsing midway is severe.
The customer is left with a half-built asset, a tender process to rerun and a completion cost well above the original price. A bond converts that open-ended uncertainty into a defined, guaranteed amount.
Bonds are typically written for a percentage of the contract value, commonly 10% for a partial bond or the full 100% on major public works. The contractor pays a premium, usually somewhere between a fraction of 1% and a few per cent of the bonded amount, depending on its credit strength, track record and the complexity of the job.
If a default occurs, the customer submits a claim and the surety chooses how to respond: funding the original contractor to finish, tendering the remaining work to a replacement, or paying the customer the extra cost of completion up to the bond limit. The important distinction is that this is a guarantee rather than insurance for the contractor, because the surety expects to recover whatever it pays out from the contractor and its owners.
Two practical nuances shape how contractors behave. A bond consumes bonding capacity, which is a finite line much like a credit facility, so bonded work crowds out other bonded work the firm might want to bid for.
An on-demand bond, which pays on presentation of a written demand without proof of default, is also far more dangerous for the contractor than a conditional one that requires the default to be established.
In practice
Real-world examples.
Example
A city transport authority requires a 100% performance bond on a $30,000,000 depot rebuild. Two of the five bidders cannot obtain bonding at that level, which effectively narrows the shortlist before any prices are compared.
Example
A commercial developer accepts a 10% bond on a $6,000,000 fit-out because the contractor has worked on four previous schemes without incident. The $600,000 cover is judged sufficient to fund the disruption of finding a replacement.
Example
A specialist steelwork subcontractor discovers that its $2,000,000 of bonds has exhausted the capacity granted by its surety. It has to decline a further tender until an existing project completes and the associated bond is released.
Formula
Calculation
Bond premium = Bonded amount x Premium rate
A regional contractor wins a $4,000,000 school building contract. The public authority requires a full performance bond, so the bonded amount, or penal sum, is 100% of the contract value: $4,000,000. The surety assesses the contractor as good quality credit and quotes a rate of 1.5%.
Bond premium = $4,000,000 x 0.015 = $60,000
That $60,000 is a real cost of the job and must be built into the tender price, roughly 1.5 cents on every dollar of contract value.
Now consider a claim. Suppose the contractor fails after completing 70% of the work, leaving $1,200,000 unpaid on the original contract. The authority tenders the remaining work and the cheapest credible replacement quotes $1,500,000.
Excess completion cost = $1,500,000 - $1,200,000 = $300,000
The surety pays the authority $300,000, comfortably within the $4,000,000 penal sum, and then pursues the contractor and its owners under the indemnity agreement to recover that amount.Case study
Seen in the real world.
This is an illustrative and entirely fictional scenario. Thornbury Civils, a fictional mid-sized groundworks contractor, held bonds totalling $9,000,000 against a surety facility capped at $10,000,000. When a $3,500,000 flood defence contract came up, the firm could not obtain the required bond and lost the opportunity to a larger rival.
The finance director had assumed bonding capacity was effectively unlimited for a profitable business. In fact the surety had set the cap against Thornbury's net assets and working capital, both of which had thinned as the firm grew turnover faster than retained profit.
The fictional company responded by retaining two years of profit instead of distributing it, tightening its debtor collection and providing quarterly management accounts to the surety. Its facility was raised to $16,000,000 the following year, which illustrates that bonding capacity is a function of balance sheet strength rather than order book size.
Watch out
Common mistakes.
- Assuming a performance bond protects the contractor, when it protects the customer and leaves the contractor liable to repay the surety in full.
- Leaving the bond premium out of the tender price, which quietly erodes margin on every bonded job.
- Signing an on-demand bond without noticing, since it can be called without any proof of default and drains cash immediately.
Questions
People also ask.
What is the difference between a performance bond and a bid bond?
A bid bond guarantees that a bidder will enter into the contract if selected, while a performance bond guarantees the actual performance of the work.
Does the bond premium depend on the contractor's finances?
Yes, sureties price on credit strength, experience and balance sheet quality, so a weaker contractor pays a materially higher rate.
When is the bond released?
Normally at practical completion or at the end of the defects liability period, depending on the wording of the contract.
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