But the other League One clubs have made 52 signings since the window opened on January 2, mostly on loan.
Former Liverpool and Manchester United players are among those to move into League One, including a midfielder who was valued at £8 million three years ago.
Ex-Posh players have also been on the move including Paul Coutts who has surprisingly dropped into Division Two after switching from Fleetwood to Salford City.
The transfer window closes at 11pm on February 1.
Here are the best of the League One signings so far...
JAYDEN STOCKLEY (Preston to Charlton): A loan move for the powerfully built striker who was often linked with Posh in his Exeter days. Photo: Tim Goode PA. Photo: PA
KEVIN STEWART (Unattached to Blackpool): Hull paid LIverpool £8 million for this midfielder in July, 2017, but released him at the end of last season and he'd been without a club until Blackpool stepped in last week. Stewart played 20 times for Liverpool and he's rejoined former Anfield coach Neil Critchley. Photo: PA
JOSH HARROP (Preston to Ipswich, loan): This attacking midfielder (right) was denied a debut against Posh at the weekend after delivering a positive Covid test the day before the game. Played one game for Manchester United in 2017. Photo: Martin Ricketts, PA wire. Photo: PA
HARRY DARLING (Cambridge to MK Dons, undisclosed): A defensive first-team regular who helped Cambridge to the top of League Two this season. (Photo by Bryn Lennon/Getty Images). Photo: Getty Images Europe