The professional services firm admitted it has spent up to 10% of the £70m budget it earmarked for the rebranding. But it defended its rush to devise the Monday brand in the light of last week's revelation that the company be bought by IBM for £2.2bn and the Monday name dropped along with the planned initial public offering.
The company claims that takeover talks only started on July 18, five weeks after the Monday branding, devised by Wolff Olins, was unveiled.
IBM will integrate PwC Consulting with IBM's Business Innovation Services to create a unit focusing on business consulting and technology services within IBM Global Services. IBM has confirmed that it will be "named under the IBM brand".
A spokesman for PwC Consulting said it had spent "a small portion - less than 10% of its global £70m rebranding budget. Most of this is thought to have been ploughed into the legal checking required to register a global trademark.
The spokesman added: "The work done to date was necessary to prepare for the IPO and to clearly signal our separation from PwC."
Aside from a few press ads in global financial newspapers to announce the name in June, no media space has been booked due to Securities and Exchange Commission rules, which prevent companies from advertising prior to flotation, as it might influence the stock price.
Charles Trevail, chief executive at brand consultants Futurebrand, applauded the decision. "IBM has been absolutely focused on the IBM brand and not tolerated any diversion from it. IBM already stands for consulting so why would it need another brand?"
As for speculation that IBM might try to sell Monday, Trevail said: "It got such a panning when it launched that it is already quite a damaged trademark. It should just give it back to the week."