Spurs technical director Franco Baldini has been in the Spanish capital to hold talks with Madrid and there are suggestions that a deal could be announced as early as Friday.
Any deal for the 24-year-old will not be publicised prior to Madrid's friendly with Al Sadd on Thursday evening as the club do not wish to overshadow the return of legendary forward Raul.
Estimations of the fee involved vary – and are complicated by the possibility that left-back Fabio Coentrao will be involved in part exchange.
However, Madrid could be willing to part with as much as 109 million euros (£93m) to secure their key summer target having already brought Asier Illarramendi, Isco, Daniel Carvajal and Casemiro to the club on permanent deals.
Various sources indicate that talks with Bale are now reaching a conclusion.
Bale has been omitted from the Spurs squad to face Dinamo Tbilisi in a Europa league play-off on Thursday night due to a foot injury.
In his pre-match press conference on Wednesday, manager Andre Villas-Boas said reports that Bale was close to joining Madrid were "not true".
However, it now appears the Wales international – who last season enjoyed a clean sweep of English football’s individual awards – is close to securing a move to the Bernabeu.
Bale’s likely fee will eclipse the £80m Madrid paid for Cristiano Ronaldo in the summer of 2009 and take the Spanish club’s summer spending to the £156.8m mark.