Celtic have made a habit out of cashing in on some of their best talent over the years, including exciting Portuguese forward Jota last summer.
The likes of Virgil van Dijk, Victor Wanyama, Kristoffer Ajer, Odsonne Edouard, and Moussa Dembele have also been sold on by the Hoops after enjoying successful careers in Scotland.
Current Bhoys star Matt O'Riley has been linked with a move to Leeds United ahead of the upcoming summer transfer window, and Brendan Rodgers may need to fight to keep hold of the Denmark international.
However, the Hoops must also be aware that there is no guarantee that a player's value will stay the same or increase if they opt against selling them, as they found out the hard way with Olivier Ntcham, who they had a nightmare with.
The bid Celtic rejected for Olivier Ntcham
The Scottish giants swooped to sign the central midfielder from Premier League side Manchester City in the summer of 2017 for a reported fee of £4.5m, with Rodgers hailing him as "gifted" and "powerful" at the time.
Ntcham enjoyed a terrific debut campaign with the Bhoys, scoring nine goals and assisting six in 49 appearances in all competitions, and this led to interest from elsewhere.
Scottish Premiership
30
5
2
League Cup
2
0
0
SFA Cup
5
3
1
Champions League (including qualifiers)
9
1
3
Europa League
2
0
0
As you can see in the table above, the Cameroon international played regularly domestically and in Europe for the Hoops, and chipped in with goals and assists on a semi-regular basis.
GOAL reported in the summer of 2018 that Portuguese giants Porto came in with an offer of £13m to sign the dynamo but it was rejected by Celtic, who were not willing to sell him, and that turned out to be a howler from the club.
Olivier Ntcham's Celtic career after 2018
The talented whiz missed 24 matches for club and country through injury during the 2018/19 campaign, which restricted him to 37 appearances in all competitions for the Hoops.
After another 18 months of action with the Scottish side, Ntcham left to join Marseille on loan for the second half of the 2020/21 season in Ligue 1, where he played just four times in the league.
His contract with Celtic then expired in the summer of 2021 and he moved to join Swansea in the English Championship on a free transfer that year.
He departed from Parkhead after four years, 147 competitive appearances, 24 goals, 13 assists, and nine trophies won after his move from Manchester City in 2017.
Whilst the club may look at his achievements on the pitch, with his attacking contributions towards their impressive trophy haul during that period, as justification for the £4.5m they spent on him, it is hard to argue against them having messed up with the rejected bid from Porto.
They turned down a chance to make a huge profit, of £8.5m, on the Cameroon international and then allowed him to walk away for nothing three years later.
This shows that they had a nightmare as they did not have a chance to benefit financially from the success he had on the field, despite having the chance to do so when the bid arrived at their desk, as his value dropped from £13m to £0 when Ntcham left for nothing.