The investigation follows concerns from other shareholders that the American billionaire may be receiving preferential treatment in the buying of shares.
Kroenke, the club's single largest stakeholder at 28.3% ahead of Uzbek billionaire Alisher Usmanov, last year accepted an invitation to join the club's board and last week his company bought 4,839 shares from members of the Carr family.
Kroenke takes Arsenal shareholding over 11 per centShould the Kroenke Sports Enterprise group holding reach the 30% threshold, they would be obliged to launch a formal takeover.
Arsenal, however, are adamant there has been no improper behaviour nor any rules broken.
The AST – whose members hold around 3% but act as the voice for small shareholders who together own about 12% of the shares – have welcomed the involvement of Kroenke and believe everyone must pull in the same direction.
"The AST regrets that a shareholder has chosen to involve the takeover panel," a statement said.
"Their complaint is about protecting shareholder value. We represent Arsenal supporters who own shares as custodians of the club.
"Our primary interest as shareholders is what is good for Arsenal Football Club rather than trying to make money.
"Once again we would urge all of the major shareholders in the club to reflect that Arsenal would be much better off if everyone worked together.
"It strengthens our resolve to work to increase the number of Arsenal supporters who own shares in Arsenal."