The Rangers boss believes the club, including former owner Sir David Murray, and fans are owed answers over the so-called 'Big Tax Case'.
An upper tier tax tribunal judge last week dismissed the appeal by Her Majesty's Revenue and Customs (HMRC), which argued that payments made from the benefit trusts to players and other employees should be taxable.
The Murray Group, who formerly owned Rangers, argued they were loans. The ruling effectively substantially reduces HMRC's £46.2m tax demands, about three-quarters of which referred to the liquidated oldco Rangers club.
Speaking to Sky Sports News at Edinburgh airport as the squad flew out to begin a pre-season tour of north America, McCoist said: "I'm absolutely delighted for Sir David Murray. Sir David actually said also that there are no winners in the case and that doesn't seem to be too far away from the truth.
"I think it's a little bit, if anything, satisfaction for the club, for our ex-players, for the supporters, for everybody really, but at the same time, I won't lie, this will slightly leave a bitter taste in the mouth after what has happened to us in the last two or three years.
"Everybody's got an explanation to do - probably HMRC, the people that pursued it - there's a lot of questions that now have to be answered.
"You don't want to look back, we want to look forward, but at the same time the relevant authorities will have to explain one or two decisions.
"Sir David Murray deserves one or two answers as well. I'll be watching with interest to see the outcome perhaps of one or two statements and one or two questions that hopefully will be answered."
The upper tier tribunal has ordered that some of the payments be re-examined, including termination and "guaranteed bonus" payments.
The case played a part in the club entering administration in February 2012 before oldco Rangers was liquidated in June the same year. The club was relaunched as a new company and the judgement has no impact on the current Rangers regime.