Why? It’s just like a clocked bus; you leave enough time for the levels to propagate along the transmission line and settle before closing the register gates.

Why? It’s just like a clocked bus; you leave enough time for the levels to propagate along the transmission line and settle before closing the register gates. All orders are placed at the previously known tick price and later orders will occur at the price declared on the next tick. Of course no trader should access the “ghost price” before it is announced on the tick. Propagation delays remain limited to local data centers and in any case it’s about globally known prices. Where’s the arbitrage here?