Blackburn, Leeds and Nottingham Forest have been hit with January transfer embargoes for failing to adhere to Financial Fair Play rules.
The three Championship clubs all exceeded the maximum permitted 'deviation' between operating loss and shareholder investment of £8m and will now have to stay within a deviation of below £6m in order to ensure the embargo is lifted at the end of the current campaign.
A Football League statement said: "An initial analysis of Financial Fair Play submissions from the current 24 Championship clubs has indicated that three clubs – Blackburn Rovers, Leeds United and Nottingham Forest – have failed to meet the Fair Play Requirement under the division’s Financial Fair Play rules.
Whilst the ruling will clearly present some difficulties, we will of course respect the rules of the Football League.
"Consequently, all three will be subject to an ‘FFP embargo’ under Football League regulations from January 1, 2015 for the remainder of the current campaign."
Rovers were first to react to the news. Managing director Derek Shaw said: “Whilst the ruling will clearly present some difficulties, we will of course respect the rules of the Football League.
“A lot of effort and hard work has been done to reduce player costs over the last two years, but we have wanted to rebuild and challenge in this division at the same time, and we will continue to do that.”
Exceptions to the embargoes will be made in certain situations such as the club requiring a goalkeeper on an emergency basis or if the club has 24 or fewer "established players", which is described as players aged 21 or over who have made at least five starts for the club.
In addition, the statement confirmed: "It [the investigation] will also now consider submissions from the three clubs promoted to the Premier League and the three clubs relegated to League 1 at the end of the 2013/14 season."