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When an invitation to bid (ITB) is issued to a general contractor or subcontractor, it sets in motion a kind of courtship where contractors vie for the attention and trust of the project owner or procuring entity – for the purposes of this article, the project client. It’s not enough to select the best firm for the project; to ensure their project maintains momentum, the bid proposal they consider must also be sincere.
The Miller Act of 1935 in the United States was aimed at ensuring tender security in federal construction projects. The Act developed regulations to promote accountability and fair competition in the bidding process, protecting the interests of taxpayers – this was the origin of the concept of bid security for the construction industry. Tender security calls for the bidding contractor to put their money where their mouth is.
This blog post explores the concept of bid security and its role in facilitating an effective and secure bidding process.
Bid security is a financial safeguarding mechanism that protects the construction project client from failure on the part of the winning bidder to follow through on their bid.
For the bidder, it’s a way of demonstrating the legitimacy of their bid, their credibility, and readiness to fulfill their contractual obligations. For the client, it’s a way of sifting out frivolous bids to leave only the serious contenders in the race. For this reason, bidding contractors offer bid security in response to an invitation to bid. If the winning bidder defaults in any way, they forfeit the funds set aside, which are then paid out to the client.
When a winning bidder defaults, it delays the project. It costs the client more time and money to re-tender and choose an alternate bid winner. Bid security compensates for this at a value calculated as a percentage of the budget estimate of a procurement requirement. The actual percentage amount varies depending on the size of the project, commonly starting with 5-10% of the total estimated project cost, potentially up to 20% of the bid price on large federal and public projects.
The bid security amount can be calculated at a percentage of the bidder’s offer or at a percentage of the allocated budget for the procurement requirement. If the procurement method does not permit revealing the allocated budget, a fixed amount is set or a percentage of the bid.
The bid security is submitted along with the tender proposal during the bidding process in the form of a bond, unconditional bank guarantee, check, or letter of credit within the timeframe stipulated by the procuring entity. This guarantees that if the client should award the contract to a particular contractor, the contractor will not withdraw their bid within the period designated for bid acceptance. Furthermore, that contractor will provide the necessary performance and payment bonds as the final assurance that they will execute the contract.

During this important phase of construction procurement management, the question burning in the client’s mind is: Is this contractor a reliable choice? By providing bid security the contractor can demonstrate their professionalism and that they are a serious contender. So, how do contractors go about obtaining the bid security funds that will enable them to compete?
The process begins upon receipt of the Invitation to Bid or Request for Proposal from the client. The contractor reviews the documentation, which will list the kind of bid security required, and the amount. Once these criteria are understood, the contractor can prepare the next actions to take to fully satisfy the bid security requirements.
Depending on the bid security type, the contractor approaches a financial backer in the form of a surety broker or bank. Surety companies help with bid bonds while banks can help with letters of credit, cash guarantees, or checks.
The onus is on the contractor to evince professional and financial stability to get good terms from the surety or financial institution. They submit their bid security application along with specifics of the project, the bid amount and validity period, and any other information required by the surety or bank. Other pertinent details include information about past and current projects, finances, business practices, and creditworthiness.
The bank or surety reviews the contractor’s application, a process that depends heavily on the accuracy and thoroughness of the submission. Based on the information provided, the project risk is evaluated against the contractor’s financial stability, and if the bid security is approved, it is issued in the format stipulated in the bidding requirement documentation.
The surety broker provides a bid bond to guarantee that the contractor will adhere to the conditions set out in the client’s bid invitation. For other types of bid security like checks or letters of credit, the bank compiles the paperwork necessary to guarantee the correct allocation of funds. With the bid security in hand, the contractor then submits their bid to the project client along with all other required documents in adherence to the bid criteria.
It is a painstakingly detailed process and, given its importance, demands attention and preparation. For contractors in construction, the bidding process is the first crucial shot at landing a project. So, projecting an image of reliability and competence is vital – and that starts with getting bid security right. To round off our tips for obtaining bid security, we recommend the following best practices:

A secure, robust bid process sets the tone for the smooth and successful execution of a construction project. It's worth noting the wider ramifications of a secure bid process versus the lack thereof:
As securing the bid process becomes an exercise in compliance to support the important choice of winning contractor bid, there are some downsides to consider.
Project clients can temper these downsides by ensuring that the criteria stated in their solicitation documentation are beyond doubt and confusion, but also contextually appropriate. For example, they should consider the state of the market to create reasonable bid security specifications that would not unfairly disadvantage smaller but qualified contractors. They should also regularly review and adjust their policies to align with industry best practices and the scale of their projects.
So, while it’s true that compliant construction bidding depends on a secure process, a competitive bidding environment depends on balancing the benefits with the potential downsides. Clearly defined and communicated criteria within the context of larger market dynamics is the best-case scenario to build on.
As project owners seek to secure the construction bidding process, they base their choice of bid security type on the nature and size of the project, the contract requirements, and the laws and regulations governing both the bidding process and their location. The most utilized types include bid bonds, checks, cash, and letters of credit.
There can be some confusion over what is bid bond versus what is bid security as some bidders mistakenly use the terms interchangeably. A bid bond is actually a subset or type of bid security, which is the overall concept.
Let's break down the various types of bid security for clarity:
The bid bond is the most common type of bid security, utilized in many construction bids to satisfy bid security requirements. It is typically issued by a bank or an insurance company that stands surety for the bidding contractor. Bid bonds provide assurance that the bidding contractor is financially stable and committed to completing the contract at the stipulated bid price – it supports the project client’s construction cost control efforts.
If the winning bidder breaches the terms of the bid, the bid bond guarantees the client is protected financially and has recourse against any losses incurred.
As previously detailed, the contractor works with a surety broker to calculate the bid security amount at a percentage of the bid amount or a fixed amount as per the bidding requirements set out by the client in the ITB. The surety broker assesses the contractor’s ability and readiness to fulfill a contract, looking at:
Once the surety broker has done their due diligence and reviewed the contractor’s compliance, they issue the bid bond, and the contractor can submit it along with the rest of the bidding documentation. If the contractor lands the project, they are obligated to follow the terms of the contract exactly, which includes offering up the performance or payment bonds required to guarantee the completion of the project. The bid bond may then be returned to the winning bidder.
If, for whatever reason, the winning contractor fails to sign and execute the contract, the contractor forfeits those funds while the client is entitled to ‘call’ the bid bond as compensation. The surety broker pays the funds to the client. The client uses the funds to cover the difference between the winning bid and the next highest bidder, or the cost to re-tender the project. The contractor then remunerates the surety broker.
Checks are often the bid security type of choice for smaller, private projects. Contractors can get a cashier’s check issued by their bank or financial institution, signed by a cashier. The check is guaranteed by the institution with funds drawn from its own reserves unlike personal checks, which draw funds from an account holder’s account. Backed by the financial institution’s creditworthiness, the cashier’s check is a safer, more reliable prospect that assures the project client that compensation will be available if required.
Where the project client places fewer restrictions on the bid security types that are acceptable to them, a certified check is a feasible option. It is a personal check made out by the account holder, certified by their bank, that shows the bank has set aside an amount of money and that the account holder has sufficient funds to cover that check. This serves as a guarantee that the check will not bounce due to insufficient funds.
Both certified and cashier’s checks provide assurance that the bidding contractor has the financial capacity and intention to execute the contract. From a simplicity point of view, checks are often preferred due to:
Checks are as valuable as cash, and so they must be handled securely to prevent theft or loss. Another best practice tip for using checks as bid security: keep meticulous records. In fact, document everything, including receipts. Once the bidding process ends, these records will help with the retrieval or voiding of checks.
An irrevocable letter of credit is issued on behalf of the bidding contractor by a bank guaranteeing payment under stated terms. As it typically requires a contractor to be established and have a strong relationship with their bank, it provides an added layer of security. Once issued, it cannot be changed or revoked without the agreement of all the parties involved, including the beneficiary – in this case, the construction project client.
The primary function of an irrevocable letter of credit in secure bidding is to assure the project owner that the funds are available and will be paid if the winning bidder fails to sign the contract or meet other obligations such as providing performance bonds. It serves as a high level of financial assurance that the contractor is capable of and committed to the stated construction specifications outlined in the bid.
The process starts with the bidding contractor approaching a bank they have relationship with:
When a winning bidder defaults, the project client shows the letter of credit to the issuing bank to claim the assured funds – it's a simple procedure because the bank has already allocated the amount of money requested for bid security.
It is less commonly used for bid security; however, cash is acceptable for small, private projects.
It becomes less viable for projects with a substantial procurement budget. When a client accepts large sums of cash as security, they are stuck with the responsibility of managing it securely and transparently. The other downside is that the bidding contractor might find themselves out of pocket and unable to complete other projects they have in development.
All the same, it does serve to demonstrate strong commitment on the part of the bidding contractor. The contractor makes a cash deposit of a specific amount, which the client retains as compensation for losses incurred when a winning contractor defaults on their bid obligations.

The concept of bid security can be summed up as a failsafe – fundamental to a fair, competitive bidding process in the contractor procurement phase of a construction project.
The provision of bid security in the tender process guarantees that only contractors who are serious about their proposals and able to fulfill the contract if awarded, participate in the bidding process. It plays an important starting role in efficient bid management in construction projects by mitigating the risks involved in contractors defaulting on a bid or failing to fulfill contractual terms.
Both sides of the bidding process – the construction project owner or procuring entity and the bidding contractor – should ensure they understand the different types of bid security and how each works. To avoid confusion at the outset, they should be sure to differentiate between what is bid bond versus what is bid security. And all stakeholders must ensure that lines of communication in construction are kept open, procurement and bidding requirements are clear, and terms and conditions contextually relevant.
Ultimately, the benefits of tender security extend beyond securing the bid for one construction project – as it enhances the bidding process in general, it helps create a competitive and fair environment that benefits all the parties involved, supporting compliance and contract integrity across the construction industry.
Another key to your success is professional bid management software. To inject efficiency into the tendering process, our RIB Candy tool offers state-of-the-art bid management features to help you optimize proposal preparation, execution, and contract and order management. Ready to simplify your entire workflow from proposal submission to successful order execution? Get your free RIB Candy demo now!

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