In an open auction everyone can see the rival's price and bid on top of it; in sealed bidding each supplier submits one real price without knowing what rivals quoted — or even how many offers arrived. MarbleMap runs on sealed bids; it holds no open auctions and no reverse auctions.
In the open format the numbers scroll across a live board: a supplier watches where the competition sits and undercuts it round after round. That is a contest of tactics, not of cost — the winner is rarely the best firm, just the one with the nerve to cut last.
With sealed bids the price is submitted once, in the dark. The note on the demand screen says it plainly: Bids are sealed — competitor offers and counts are hidden. Buyers cannot see one another either. Only the buyer who opened the demand sees the offers as a whole, lines them up with Compare shortlist, and gets the most advantageous one flagged automatically — the final call always rests with a person.
One more difference: an open auction has a single dimension, the lowest figure. In sealed bidding the buyer weighs delivery point, Incoterms and lead time alongside price. And since MarbleMap takes no share of any sale and earns only from subscriptions, nothing is gained by nudging the outcome.
Also asked as: Do you run auctions? · Is this a reverse auction? · Are bids open or sealed? · What bidding format do you use?