There’s a model they follow and Celtic have had some real success in the transfer window this last decade.
While an academy star like Kieran Tierney has been sold for £25m, the Hoops have also implemented a buy low sell high model effectively. That has a few stars in their current ranks forming the centre of summer rumours this transfer window, with big profits likely en route.
Outside that, a player in Glasgow is judged by their trophy haul in most cases and all of these Celtic players of the present and past can count a fair amount of silverware. They all have made a serious impact in Hoops, whether that be on the park, or what they brought into the club when leaving.
Taking a look over the last 10 years, we take our picks for the 13 best moves in no particular order that Celtic have made in that time.

1. Jota
Came in on loan and made himself a fans favourite. Club had to spend big to get him back but that was more than made up for with a £25m fee paid last summer. An ideal example of how Celtic should be looking to trade. | Getty Images

2. Stuart Armstrong
Arriving in the summer of 2014 in a £2m double deal with Gary Mackay-Steven from Dundee United, he went on to make 144 appearances in Hoops with eight trophies in just three years. His hair is fine was a terrace favourite all the time. | Getty Images

3. Moussa Dembele
Signed for a compensation fee of £500k in 2016 and Celtic certainly got bang for their buck out of it. 51 goals in 94 outings plus eight trophies, then leaving for just shy of £20m. Enjoyed success in Ligue 1 with Lyon and is now playing in Saudi Arabia with Steven Gerrard's Al-Ettifaq. | Getty Images

4. Cameron Carter-Vickers
£6 splashed on the centre-back after his arrival from Tottenham, initially on loan. Celtic look a different team without him playing and rightly established himself as one of the best defenders to pulled on Hoops this last decade. | SNS Group