Last trading day
The final day on which a contract trades before it moves to settlement.
How to read the number
Until that day a position is closed by an ordinary trade. After it, closing is no longer possible and only settlement under the specification remains.
When the metric lies
Liquidity leaves for the next series well before the deadline. Whoever holds to the end trades in a nearly empty book, where the exit price is set by the single counterparty who is still there.
Also known as: final trading day