Wenger said that the club had the £42.5m for the signing of Mesut Ozil in the bank, which meant that he was happy to bring the player in.
"I fight for the teams to spend the money they have made and not artificially earned," BBC Sport quotes Wenger as saying. "Once we have made that money I am happy to spend it. It is also important for us to find world-class players.
"We had to go through some years where we had restricted financial potential. We are now in a stronger position financially.
"Honestly, I think [Ozil's signing] was linked with Gareth Bale's transfer. I don't know exactly what happened inside Madrid. Was it down to financial reasons? Maybe they had to let someone go, I was surprised."
Ozil is in line to make his Arsenal debut against Sunderland on Saturday.