Newcastle director Mehrdad Ghodoussi admits they battled to control agents during the January market.
Sevilla centre-back Diego Carlos was among the players heavily linked with a January move.
And it is reported the Spanish club rejected bids around the £30million mark for the Brazilian.
Ghodoussi, who is Staveley's husband, told The Athletic: “It was hard.
"Agents were leaking information, selling clubs would leak, you'd see your name associated with god knows who.
“Not only was it a difficult window, but everybody was thinking we had money to throw around.
"We walked away from deals because of that. We can't set a precedent that we are there to buy at any cost."
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