After victory over Reading, Wenger said: "We have always kept our players together.
"What has been changed is that there is a new rule which allows players to leave after three years. You are always confronted with potential instability.
"Players are admired all over the world, they are tapped up, agents get nervous and they see if they can do a deal.
"Before, when you had a player under contract for five years, they were your player for five years; now, they can leave after two years under the age of 28."
Wenger added: "For a club like ours, which is going for a youth team policy, this rule is very detrimental.
"We educate them and then they could leave at some stage when they get mature.
"This rule is not good and we live in a world where it is also an incitement to inflation because you are always having to look at their contracts."