The winter transfer market has been seen by many managers as a mid-season distraction, but in recent years, more and more managers are dipping into the market to add reinforcements to their squads.
But which are the most expensive January signings of all time? Camisetasfutbolsorpresa.com has explored the ten most expensive transfers to date.
10. Diego Cosa, £52m, Chelsea to Atletico Madrid, 2018
Chelsea are once again involved in major January deals, this time with Diego Costa. He led the Blues to two Premier League titles, playing a key role under now-Tottenham manager Antonio Conte. Costa scored 52 goals in 89 appearances before returning to Spain for a second spell at Atletico Madrid.
The Spaniard's career has since taken a dive and after a year out of the game, he returned to the top flight when he joined Wolves this summer.
9. Bruno Fernandes, £54m, Sporting Lisbon to Manchester United, 2020
Bruno Fernandes has become one of the Premier League's finest players since joining Manchester United three years ago. The Portuguese international has already made 100 appearances for the club and is Erik ten Hag's key man.
His price seems a bargain after the impact he has had for the Red Devils.
8. Pierre-Emerick Aubameyang, £55m, Borussia Dortmund to Arsenal, 2018
The Frenchman is another player who has made a big-money move to England, and he hit the ground running in north London, scoring ten goals in 12 starts. He would go on to score 68 goals in 128 games for the Gunners before things went sour under manager Mikel Arteta.
Aubameyang was frozen out at the club and after four years, he moved to Barcelona before returning to the Premier League this season with Chelsea.
7. Christian Pulisic – £57m, Borussia Dortmund to Chelsea, 2019
A year later, Christian Pulisic joined the list, following Aubameyang to England from Borussia Dortmund. Pulisic became Chelsea's second most expensive signing after Alvaro Morata and was loaned to Dortmund for the remainder of the season after joining.
His form has declined over the past two seasons, but he remains a key asset for the Blues.
6. Aymeric Laporte –£58m, Athletic Bilbao to Manchester City, 2018
Aymeric Laporte joined Manchester City during their title-winning 2017/18 season but didn't immediately break into the starting lineup. However, he has become a regular in Pep Guardiola's side and has been impressive at the heart of the defence with his ability on the ball.
Laporte has won four Premier League titles, as well as one FA Cup and three Carabao Cups.
5. Dusan Vlahovic, £ 71m, Fiorentina to Juventus, 2022
In the only transfer not to include a Premier League side, Dusan Vlahovic joins some big names with one of the most expensive transfers. The Serbian striker joined Juventus last year after Cristiano Ronaldo returned to Manchester United, leaving a space for a goalscorer in Turin.
He has yet to make a big impact on the team since joining the club after injuries affected his form.
4. Virgil van Dijk, £74m, Southampton to Liverpool, 2018
Virgil van Dijk joined Jurgen Klopp's side, and was the most expensive signing to date. The price paid has been worth it as the player has been one of the pillars of the team and the main man in Liverpool's defence and many claim that he is the best Premier League defender of all time.
Van Dijk lifted the Premier League title in 2019 as he guided the Reds to their first ever win.
3. Mykhaylo Mudryk, £80m, from Shaktar to Chelsea
Shakhtar Donetsk's young Ukrainian footballer could cost up to 90 million if all conditions are met. With a high projection, the 80 million pounds initially paid places him as the third most expensive signing in the history of winter transfers.
2. Enzo Fernandez, £106.8m, Benfica to Chelsea, 2023
After much negotiation against a Benfica very reluctant to let go of its star player and recent world champion with Argentina in Qatar, Chelsea has managed to close the signing of Enzo Fernandez, making this the most expensive signing in the history of the club. Premier League. 
1. Philippe Coutinho, £117m, from Liverpool to Barcelona, 2018
He became one of the most expensive players of all time after joining Barcelona, but the move marked the end of his European career. Coutinho faded in popularity and went on loan to Bayern Munich before joining Steven Gerrard's Aston Villa early last year.
He has signed a permanent deal with the Villans and is looking to regain his best form under Unai Emery.
