Palmer told BBC Radio Nottingham "We absolutely don't need to sell. When you are doing well and have players that are doing well, you are going to attract interest. But at the moment's it's not important to us.
"With the budget we had at start of the season, we understood there was an amount we would need to put in to the business - the owners understood that.
"We have actually cut that in half effectively already because of the crowds we've had this season, so we are in a good place.
We don't have any unexpected losses... and we have more freedom to think this season.
"You see a lot of clubs, smaller clubs, that are achieving big things through a lot of owner funding.
"That is not the model we want to take, we want to do it in a sustainable way. Unfortunately, that's not how it has been in the past and the club has run into trouble as a result of that.
"Something the fans want to hear the most is that the club is on a firm footing, is stable and is wanting to head toward sustainability and achieving growth.
"The modelling we have done at the moment would say that we can easily sustain ourselves in League One and probably in the lower Championship.
"For me it's about going as far as we can with being sustainable, and if you look at it in terms of fan base and size of our stadium then probably the top of League One or lower Championship is where that sits within the football eco system."