They seems to also know the standings (how well are you doing this season), how did you played in the cup based on your division(thoug the seems to be unable to understand that there is a difference between losing a V div team and I div team).
Finally they seems to trust their manager view of the market because, apparently, the don't know wheter that 18yo player you bought is good or not or if the 40k PG is a monoskill passer or a balanced player. But they do know how much did you spend on them, an based on that, they probable assume you will only spend good money on good players. For the same reason, probably they can't recognice a good deal (something cheap) because, "if the player wasn't exoensive, it can't be that good".
Those are just my thoughts on it. I haven't read any BB talking more details about this.