MacAnthony saw former Posh star Sammie Szmodics head to the Premier League.
Szmodics has signed for Ipswich Town, having left Blackburn Rovers for as little as £9 million.
“A great move for him. I cannot believe that deal. I am f*****g stunned. I was stunned. Nine million quid!” MacAnthony said in his The Hard Truth podcast.
“I don’t give a f*** if he’s 28, if you did your homework, he’s the type of player who will play until he’s 35 based on how he plays.
“I cannot believe for the life of me why some of the top teams in the Championship - and Ipswich is a massive club, don’t get me wrong - but there are some big clubs in the Champ. I cannot believe nobody, nobody went in and sniffed at £12, £13 or £14 million.
“I said the other day, when you pay over three years or four years and you add the player’s wages in, you’re probably talking about £5 million a year on a four-year deal or whatever.
“For a player that basically will guarantee you top six in the Champ, which gives you a one in four chance of the play-offs and getting to the Premier League or one in two if you’re in the top two of going up automatically. I cannot f*****g believe it.
“For a player to go for that kind of money, I don’t know what’s gone on with the market this summer because I’ve seen players who are half that player go for £15, £16, £17 million from the Champ. I don’t know what’s going on.
“The worst part is, people say it might be a flash in the pan. The m*********r was already leading goalscorer in cup and league games this season inside one and a half sub appearances or whatever. I can’t believe it.
“Then I couldn’t believe, fair play to Ipswich, that it wasn’t even up front, it was all over time because we’ve got to wait for our segment.
“When I get the text through with the amounts from Baz (director of football Barry Fry), I thought somebody had made a f*****g helluva bid for one of our players. I thought it was the payment and rang Barry and I said, ‘F*****g hell! Four (million) up front or whatever else’. And Barry was like, ‘No, no, no…’.”
He added: “A helluva deal for Ipswich, a helluva deal for the boy because he’s from that neck of the woods, Colchester, Ipswich is down the road.
“I’m proud as anything because you’ve got Ronnie (Edwards) in the Premier League (at Southampton), Jack Taylor in the Premier League (with Town), Ivan (Toney) in the Premier League (Brentford), Sammie in the Premier League. All those players were with us around Covid.
“Quite a few of them we might have paid seven figures for but they were all with us around Covid and Harrison (Burrows) could be there next year.”