FIFA has banned third-party ownership as a threat to the game's integrity because investors force transfers to make a profit.
The Football Leaks website last month published a contract between Twente and Doyen in which Doyen agreed to pay Twente 5 million euros ($5.3 million) for between 10 and 50 percent of the transfer fee rights for seven players. The deal was signed in 2014, before FIFA outlawed third-party ownership.
The KNVB said the sanctions were imposed by its licensing committee. The association also is sending Twente's dealings with Doyen Sports to the KNVB prosecutor and to FIFA.
"They have to judge whether the contract between FC Twente and Doyen Sports breaches national or international football rules," the KNVB said.