Chief executive Derek Bowden says that Town will be having more concerts next year despite neither of this summer's events selling out. The club made an undisclosed profit from the performances by Neil Diamond and REM.
REM attracted 23,000 fans and Diamond brought in only 17,500, while the club also held a meeting of the Mothers' Union of England.
Bowden says the club plans to continue to put on concerts next summer: "I am sure we will have something in 2006. Last year we had Elton John and that was also very successful, both financially and from the point of view of the public.
"We might have another big name or maybe two smaller concerts, we don't know yet, but there is no doubt that we want to do it again."
The club's original plan was to stage a number of concerts within the same week during the close season and they could look to do this next year. Bon Jovi were in negotiations to play Portman Road this summer, however they put off their European tour for a year but could well be one of the acts pencilled in for 2006.
The failure of the concerts to sell out was not something which was unique to Town. Other clubs also reported similarly slower sales, Hull City selling only 18,500 REM tickets out of 23,000.
KC Stadium marketing officer Rob Smith admitted ahead of last week's event that there had been lower than expected interest: "Financially and commercially, it is disappointing. It has moved a little in the last week and we are expecting 18,500.
"That, by most people's standards, is very good but we set our standards higher than that and we wanted it to sell out.
"REM still have to be considered one of the world's biggest bands but maybe this is a sign of the times.
"We would have expected an artist like this to sell out fairly comfortably. But we've just got to take this on the chin and move on."
Nicola Wood from the NME suspects the sheer number of big concerts this summer could have affected ticket sales: "REM are a great band and are still making very good music and are still very popular.
"I have no idea why tickets are not selling. It could be because they have just performed at Live 8 and there are loads of festivals on at the moment."