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Estimating & Bidding

Sealed Bid

In Plain English

A bid submitted in a sealed envelope that no one can see until all bids are opened at the same time.

Definition

A sealed bid is a bid submitted in a sealed envelope or secure electronic format that is not opened until the official bid opening, ensuring all bidders compete without knowledge of competitors' prices. Sealed bidding is required on most public construction projects to ensure fairness and transparency. Bids submitted after the deadline or in unsealed form may be rejected.

Why It Matters in Bidding

Sealed bidding is the legal default on most public construction work because it enforces fairness — no bidder learns a competitor's price before the official opening, which prevents collusion and last-minute undercutting. For contractors this raises the stakes of bid-day timing and accuracy, since a bid that arrives late, unsealed, or improperly signed can be rejected outright as nonresponsive regardless of how competitive the price is. The public bid opening also creates a transparent record that competitors and the public can scrutinize.

Example

All seven general contractors submitted sealed bids before the 2:00 p.m. deadline, and at the public bid opening the agency read each price aloud, revealing the apparent low bidder by just $12,000.

Related Terms

Bid OpeningCompetitive BiddingBid DayBid

Frequently Asked Questions

At the advertised date and time, an agency official publicly opens each sealed envelope or electronic submission and reads the bid amounts aloud, recording them on a bid tabulation. Bidders and the public may attend. The apparent low responsive, responsible bidder is identified, though award follows verification of bid bonds, math, and solicitation compliance.
Before the deadline, a bidder may withdraw or resubmit freely. After opening, changes are generally barred to preserve fairness. A bidder can sometimes withdraw without penalty by promptly proving a genuine clerical or arithmetic mistake, but cannot simply revise a price that turned out too low, which is why bid-day math review is critical.
Public procurement laws mandate it to ensure transparency, equal treatment, and stewardship of taxpayer money. Keeping prices confidential until a simultaneous opening prevents bid-rigging and favoritism, while the public reading creates an auditable record. Private owners are not bound by these rules and may negotiate or use open bidding, but public agencies must follow it.

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