A block trade is a large transaction negotiated separately from ordinary order-book matching under the applicable market rules. The term describes how a sizable position changes hands; it does not mean a transaction inside a blockchain block.
How a block trade works
A buyer and seller, sometimes through a broker or a request-for-quote service, agree on an asset, quantity, price and settlement terms. This can avoid sweeping many visible price levels to fill a large order. However, the negotiated quote may include a dealer spread, and a block trade does not guarantee a better price or eliminate market impact.
Minimum sizes and eligible participants depend on the product and venue. There is no universal token amount or currency threshold that defines every crypto block trade. Exchange-listed derivatives can also have formal block-trading arrangements outside their ordinary matching process.
Reporting and settlement still matter
Private negotiation does not necessarily mean an unreported transaction. For example, CME’s block-trade rules specify reporting and clearing requirements; those requirements should not be assumed to apply unchanged to other platforms.
Before settlement, counterparty performance and the agreed delivery process still matter. Custody arrangements, collateral and clearing can change the risks, but size alone provides no protection. A completed negotiation should therefore be distinguished from the final transfer of assets or obligations.