The 22-year-old impressed for Milan during the 2019-20 campaign, and United were said to be interested in signing him during the recent transfer window.
Bennacer has already made seven appearances for Milan this term, contributing two assists in the process.
However, despite being a key player for the Italian club, the terms of his contract state that a €50m (£45m) release clause will come into play next summer, according to Calciomercato.
Bennacer, who largely operates as a holding midfielder, represented Arsenal between 2015 and 2017 but only made one first-team appearance for the Gunners before moving on. body check tags ::