Bid and Tender Bonds: When You Need One on Australian Construction Contracts

Bid and tender bonds sit at the front of every formal Australian construction or infrastructure tender. They are smaller in face value than the performance security that follows on award, but the wording, timing and lodgement rules around them shape whether a contractor's tender is even read — let alone shortlisted.

This guide is the tender-stage companion to BCS Broking's broader surety bonds for Australian construction and mining coverage. It explains what a bid bond is, when Australian principals require one, how the face value is set, the difference between bank-issued and surety-issued bid bonds, and what happens to the bond after award.

What is a bid bond, and is it the same as a tender bond?

A bid bond — used interchangeably with "tender bond" in Australian practice — is contractual security a contractor lodges alongside a tender. It guarantees two things to the principal: that the contractor will enter the contract if awarded, and that on entry it will lodge the contractually required performance security (typically a performance bond or bank guarantee at 5–10% of contract value).

The two terms are functionally identical in Australia. Some state government works and engineering procurement teams use "tender bond"; commercial and federal procurement leans on "bid bond". The wording and structure of the underlying instrument is the same.

If the awarded contractor refuses to enter the contract, withdraws from the tender after the lodgement deadline, or fails to provide the performance security required by the contract, the principal can call the bid bond up to its face value and use the proceeds to cover the cost of re-tendering or appointing the next-ranked tenderer at a higher price.

When Australian principals require a bid bond

Bid bond requirements vary by procurement category but cluster into three main contexts.

State and federal government works. Most state transport agencies (Transport for NSW, Major Road Projects Victoria, Department of Transport and Main Roads QLD, Main Roads WA), state water corporations, and the Department of Defence's larger procurements require a bid bond on tenders above defined contract value thresholds. Thresholds vary — typically tenders above $5–10m attract a bond requirement, with larger infrastructure tenders ($100m+) almost always requiring one.

Tier 1 and Tier 2 private principals. Major mining operators, energy infrastructure owners and large private developers commonly require bid bonds on contracts above $5m, with the requirement detailed in the request-for-tender documentation rather than a public schedule.

International contracts let from Australia. Tenders run by Australian principals for offshore works (including PNG, the Pacific, and ASEAN markets) typically follow FIDIC contract families, which assume a tender security as standard.

A bid bond requirement is almost always written into the request-for-tender (RFT) or invitation-to-tender (ITT) documents under headings like "tender security", "tender bond" or "bid security". The requirement specifies the form (bank guarantee or approved unconditional undertaking), the face value (a percentage of bid value or a fixed amount), the validity period, and the acceptable issuer rating threshold.

How bid bonds are sized

Australian practice tends to size bid bonds at 1–5% of the lodged bid value, sometimes capped at a fixed dollar amount on very large tenders. State government works are commonly at 1–2.5%; private commercial and infrastructure tenders range from 2.5–5%. The face value typically holds for the validity period plus a contractually defined buffer (commonly 30–90 days) to allow for tender evaluation and contract execution.

By contrast, the performance security that takes over on award is typically 5–10% of contract value — substantially larger and longer in duration. The bid bond is the smaller, shorter-duration security that bridges the gap between tender lodgement and contract execution.

Bank-issued vs surety-issued bid bonds

The two delivery channels mirror those for performance bonds, with the same trade-offs around facility consumption and cash collateral — but compressed into a tender-cycle timeline.

For contractors that tender frequently, a surety facility is usually the more efficient structure — bid bonds can be issued against the facility on demand without renegotiating bank facility limits each time. For one-off or infrequent tenderers, a bank-issued bid bond is sometimes the fastest path if the bank facility headroom is available.

For a deeper comparison of surety vs bank-issued security generally, see surety bonds vs bank guarantees. For the structural setup of a surety facility that issues bid bonds, see how surety bond facilities work.

What happens after the tender — call, return, or convert

Three outcomes are possible at the end of the tender cycle.

The contractor is unsuccessful. The bid bond is returned to the contractor (or its issuer) within a defined window — commonly 30 days from contract award to the successful tenderer. The cost of the bid bond is the premium plus any opportunity cost of locked capacity for the validity period.

The contractor wins and proceeds to contract. The bid bond is replaced by the performance bond at contract execution. In practice this is a simultaneous swap: the contractor lodges the performance bond and the principal returns the bid bond. The instruments are separate, drawn on the same surety facility (or on bank facility lines) — the sizing steps up from 1–5% bid value to 5–10% contract value. For the wording considerations on the performance bond itself, see performance bonds: AS2124, AS4000 & AS4300 compatibility.

The contractor wins but withdraws or fails to lodge performance security. The principal calls the bid bond. The issuer pays the face value within the bond's stated payment window (typically 5–10 business days for major Australian banks; 10–30 days for surety underwriters). The principal then uses those funds toward re-tendering or paying the price differential to award the next-ranked tenderer.

The third outcome is rare but commercially serious — a called bid bond signals to other principals and to the surety market that the operator has had a tender-stage default, which can affect future tendering and surety facility renewal.

FAQ

What is the typical face value of a bid bond on Australian construction tenders?

Most Australian construction tenders set bid security at 1–5% of bid value. State government works are commonly at 1–2.5%; private commercial and major infrastructure tenders range from 2.5–5%. Some very large tenders cap the bid bond at a fixed dollar amount instead of a strict percentage.

Are bid bonds required on every Australian construction tender?

No. Bid bonds are typically required on tenders above defined contract value thresholds — commonly $5–10m for state government works, with thresholds set by the procuring agency. Smaller tenders, design-only contracts and most maintenance panels do not require bid security.

Can a bid bond be issued against an existing surety facility?

Yes. A surety facility is a master credit line under which bid bonds, performance bonds, retention bonds and other bond types can be issued as projects are tendered and won. This is one of the operational advantages over arranging a single-purpose bank guarantee for each tender.

How long is a bid bond valid for?

Bid bonds are commonly valid for the tender evaluation period plus a buffer for contract execution — typically 90–180 days from tender lodgement. The required validity period is set in the request-for-tender document.

What happens if the tender process is extended past the bid bond expiry?

The principal will request an extension to the bid bond. The issuer (bank or surety) issues a replacement or extension instrument; in most cases the contractor pays a pro-rata premium for the extended period. Refusing to extend is treated as withdrawal from the tender.

Do bid bonds count toward bank facility limits?

Bank-issued bid bonds consume bank facility headroom for the duration of the bond. Surety-issued bid bonds are drawn on a separate surety facility and do not affect bank facility limits — for high-volume tenderers this is the structural reason most operate a surety facility for tender security.

Does the surety underwriter's S&P rating affect bid bond acceptance?

Yes. Most Australian principals specify a minimum acceptable S&P (or AM Best) credit rating for the issuer of any bid security — A- minimum is the current convention on government works. The four major Australian sureties (Assetinsure/Credeq, Vero, Liberty Specialty Markets and BHSI) currently meet that threshold.

Where to next

Bid bonds are one of several surety types that share a single facility structure. To explore further:

• The surety bonds for Australian construction and mining pillar covers the full range — bid, performance, maintenance, retention, advance payment, mining rehabilitation and others
• The bid and tender bonds product page is the BCS Broking service overview
• The performance bonds guide covers the post-award security that replaces the bid bond
• The surety bonds vs bank guarantees comparison covers the broader cash and facility trade-offs

If you would like to explore whether a surety facility makes sense for a specific tender program, contact BCS Broking.

This information is general in nature and does not consider any specific objectives, financial situation or needs. Consider whether the information is appropriate before acting on it. BCS Broking Pty Ltd is an authorised insurance broker (AFSL details on the Financial Services Guide).