The club insert sell-on clauses into outgoing transfer deals as standard and that could result in a windfall this summer with ex-Hoops stars Moussa Dembele and Jeremie Frimpong reportedly attracting interest with their performances for Lyon and Bayer Leverkusen respectively.
Dembele has nine goals in 19 games in Ligue 1 this season, including five in his last seven, and that form has caught the attention of Manchester United, according to The Mail, with a potential £25m bid on the cards.
The 25-year-old joined Celtic from Fulham in 2016 and scored 52 goals for the Glasgow club before earning his £19.7m move to France two years later. His Lyon contract expires in 2023 so the club could look to sell the striker this summer rather than risk losing him for nothing next year.
Frimpong, meanwhile, moved from Celtic to Leverkusen for £11.5m during last year’s January transfer window and his Bundesliga performances have attracted plenty of admirers with Bayern Munich, Borussia Dortmund and Barcelona all credited with interest.
Celtic had to pay his previous club Manchester City a 30 per cent portion of the transfer fee recouped for the right-back, and they are understood to have negotiated a significant sell-on fee of their own in the deal that took the young Dutchman to Germany.
Leverkusen are believed to value Frimpong around the £30m mark meaning that if both he and Dembele complete reported moves this summer, Celtic could be in line to receive a portion of a combined £55m in transfer fees.