Clubs selling players

It struck me a few seasons into a game that certain clubs have a tendency to accept bids fro their players way below their true value, while others will not budge without crazy bids.

Does anyone know what drives a club's decisions regarding transfer bids for their players? I assumed it would be down to club reputation, bank balance and maybe Chairman's interference level but I've seen a few clubs accept bids at around a 1/4 of the player's value when they've had pretty healthy finances.

I've also noticed in the past that if I put in a bid of around (or just over) a player's valuation, it's almost always rejected but if other clubs bid first, they usually accept.