Waiting for prices…

This trade earns the gap between the same gold on two venues. Both legs go on at once, so the gold price nets out.

1. The spread is the gap between selling XAU on Lighter and buying XAUt on Variational.
   Open when it reaches the open mark.
2. Closing crosses both books, and the page prices it at what it would fill at — which is why the close mark sits below the open mark on the same scale, by the crossing cost shown above, and moves with the books.
3. What you keep is the spread you opened at, minus the spread you closed at, minus crossing. Open at the mark and close at the mark and that is at least $3 an ounce before funding, because the marks are set so it cannot be less.
4. The reverse runs the same trade the other way: long XAU on Lighter, short XAUt on Variational. It opens at the close mark and closes at the open mark, so it keeps the same $3 an ounce. The hedge button does not trade it; both legs are by hand.
5. The marks are the top decile of the spread and the bottom decile of the cost to close, over the window shown — so they follow the market instead of sitting at a number that stops firing.