| Quote | Value |
|---|
| Line | NPV | Notional |
|---|
On a real desk the pricing screen and the booking screen are two halves of one flow. The trader tweaks the deal until the number is right, then books it. Book carries the economics across: every leg, every schedule, every strike. What it does not carry is the interaction — the booking screen opens without a market data feed and without model inputs, because its job is the correctness of the record, not the price.
The one thing the booking screen cannot derive is the initial NPV. Book carries it with its provenance: the as-of time, the market data cut, the model, and the run that produced it. The booking screen shows it read-only.
New trade starts a deal here, from the least reference data the screen can price from: the product type, the two currencies and their amounts, the strike, the option type and the expiry. Book carries that set across, and the booking screen fills in the rest. Opening this page with a structure already booked amends it instead, which is the other half of the flow.
This prototype fakes the valuation. The number moves with the tweaks because a static number would hide the handoff, which is the point.