What is the one component impacting a Xerox sale to another company? The large amount of labor or workforce still on the books. Moving a lot of people to HCL makes it easier for Xerox to divest itself of components to other companies. No bad news for the new company by having to let go of a bunch of workers. It is now HCL's bag to hold.
At that point, HCL will let go of the rebadged workers since they no longer have the contract with that "Xerox" divestiture.
HCL makes money in the meantime charging Xerox for the labor which was rebadged. Money that they would not have made prior to the rebadging (guarantee there is a built-in profit for HCL and probably a bonus clause in the contract if the work from Xerox terminates early.)
Borrowed time is how you should look at it. Time which should be spent brushing up your resume and interviewing skills or planning for early retirement.
Good point @Ytbeujt-6pew