Is a comment bid on a static post auction legally binding — and can a bidder retract before the end time?

The bid as a binding proposal

Under Indian Contract Act Section 2(a), a proposal is when one person signifies to another their willingness to do something — here, to pay the stated amount for the lot. A comment stating '₹3,500' on a post where the bidding context is clear (caption states 'SB: ₹3,000, increment: ₹500') signifies the commenter's willingness to pay ₹3,500. IT Act Section 10A confirms this electronic proposal has the same legal validity as a physical bid at an auction.

The bid is binding as a proposal — the bidder cannot simply ignore the seller's winner announcement if they were the highest bidder at the end time. A bidder who places a comment bid and is announced as the winner has entered a binding contract at the moment of the seller's announcement. Refusing to pay after being announced as the winner is breach of contract, exactly as analysed in Q238 for WhatsApp auctions.

Retraction before the winner announcement — fully valid

SGA Section 64(b) is clear: 'until such announcement is made, any bidder may retract his bid.' A static post bidder who changes their mind before the seller posts the winner announcement can retract by commenting 'retracting my bid of ₹3,500' or similar. The retraction is valid from the moment it is posted and visible.

The timing consideration: if the seller posts the winner announcement at 8:00 PM (the stated end time) and the bidder's retraction comment was posted at 7:58 PM — before the announcement — the retraction was valid. The seller cannot announce that bidder as the winner. If the retraction was posted at 8:02 PM — after the winner announcement — the contract was already formed at 8:00 PM and the retraction came too late.

The bidding slab — does it create a binding minimum increment?

When the post caption states 'minimum increment: ₹500', this establishes a condition of the auction: bids below the previous highest bid by less than ₹500 do not count. A bid of ₹3,200 when the current highest bid is ₹3,000 (below the ₹500 minimum increment) is not a valid bid within the stated terms. The seller is entitled to disregard it or ask the bidder to rebid at the correct increment.

This is consistent with the SGA's framework that auction terms define which bids are valid. Pre-stated minimum increments are part of the auction terms — bidders who participate after seeing the caption have agreed to bid on those terms. A bidder cannot claim the contract was formed at ₹3,200 if the stated minimum from ₹3,000 was ₹3,500.

What happens if someone bids below the slab by mistake?

If a bidder posts ₹3,200 when the minimum valid next bid was ₹3,500, and the seller does not disregard it but instead announces that bidder as the winner at ₹3,200, the seller has effectively waived the minimum increment rule by their own acceptance. The contract at ₹3,200 is formed on the seller's announcement — the seller cannot later claim the bid was invalid if they chose to accept it. The minimum increment is the seller's rule to enforce, not the bidder's obligation to self-police.

Laws & authorities referenced in this chapter

Indian Contract Act 1872 — §2(a) (comment bid = proposal), §5 (proposal revocable before acceptance)

Sale of Goods Act 1930 — §64(b) (any bidder may retract before completion announcement)

IT Act 2000 — §10A (electronic bid has same legal validity as physical bid)