Reguilon returns to Spurs after unsuccessful Man Utd loan spell
Reguilon joined United on a season-long loan in September to provide cover for the injured Luke Shaw and Tyrell Malacia and has made 12 appearances in all competitions for the club.
Shaw and Malacia are both expected to be available soon.
"Sergio Reguilon is returning to his parent club Tottenham Hotspur after Manchester United activated a break clause in the loan agreement," United said in a statement.
"Sergio fulfilled the role he was brought in for: to provide cover for Luke Shaw and Tyrell Malacia while both were out with long-term injuries.
"While Luke has missed the past two games with a minor injury, the England international is expected back soon. Tyrell, meanwhile, is getting closer to a return from his knee injury."
Reguilon spent last term on loan at Atletico Madrid, having joined Spurs in 2020 on a five-year deal from Real Madrid and making 52 league appearances in his first two seasons.