Fernandes has invested heavily since becoming the majority owner of the London club back in 2011 and brought in the likes of Steven Caulker, Leroy Fer, Sandro and Rio Ferdinand after returning to the Premier League by winning the Championship play-offs last season.
Harry Redknapp has been linked with a move for Tottenham striker Emmanuel Adebayor ahead of Monday's transfer deadline as he attempts to guide Rangers out of the relegation zone.
Fernandes, though, is not expecting to be active in the transfer market.
He tweeted: "No more cheque book. We have good players. Bought all the players manager asked for in summer. Our players not mercenaries. Good guys.
"If something interesting comes up we would look at it. But I'm not optimistic. Given the right motivation, tactics and coaching we can achieve much more."
Rangers have still not picked up a point away from home this season after losing 3-1 at Stoke City on Saturday.
