Market moves are subject to opinions, and while they are more accurate data than just opinion alone. There are speculators, bookies, traders who will invest / sell purely because of market moves. If everyone starts trading out their risk as odds drop, it creates a market instructed by its own movement.
Allardyce was never wanted as a longer term appointment and he will want security and money. Allardyce is a horrible fit in the circumstances, for club and ambition. He's a manager similar to Koeman, rigid, defensive, organised, loud and the loudest prick in a room of cocks.
If you need to dig yourself out of a hole, he can raise the bar, but leaves behind a strangled turd of a team. You have to have pretty low expectations in life to think he's a good choice.