Arne Engels, Celtic's record signing, was valued at £11m in the summer of 2024.
Despite struggling to secure a starting position, the CIES Football Observatory estimates his value to be between €15m-€17m (£13.05m-£14.79m).
This valuation comes after his Champions League and domestic performances, with previous estimates ranging from £14m to £25.3m.
His current value is now comparable to Rangers' Nico Raskin, another Belgian midfielder.
The CIES Football Observatory has placed a hefty value on the young 22-year-old midfielder.
Author's summary: Engels' value is estimated between £13.05m-£14.79m.