BVB have seen the departures of key players Mats Hummels, Ilkay Gundogan and Henrikh Mkhitaryan but have replaced them with eight players and, if anything, Watzke believes they now have too many players.
Marc Bartra, Sebastian Rode, Mario Gotze, Ousmane Dembele, Raphael Guerreiro, Mikel Merino, Emre Mor and Andre Schurrle have all been added to the playing squad as they seek to close the gap to Bayern and the chief executive told the club's fans not to expect any more signings.
"As things stand, there will be no more new arrivals before the end of the transfer window," Watzke told Bild am Sonntag.
"If anything, we already have too many players at the moment.
"We will not be bringing in any key players who just won the Champions League with Real Madrid. We cannot afford to do anything more than not getting into debts and make sure we are financially stable."