Wasps have made 167 players and staff redundant after becoming the Premiership's second club to go into administration inside 21 days.
The Coventry-based club were suspended by the Premiership last week.
It is now been confirmed that they have suffered the same fate as Midlands rivals Worcester and will be relegated.
But Arena Coventry Limited, which operates the Wasps-owned Coventry Building Society Arena, may still avoid going into administration.
While Wasps Holdings Limited are the firm to have actually entered administration, ACL, also part of Wasps, has filed a new notice of intention to appoint administrators with the High Court in London.
That would allow ACL, which holds the Coventry City Council lease to operate the stadium, a fortnight's grace, which will give time to find further funding, so that the CBS Arena remains operational, and stadium tenants Coventry City's Championship home matches can still be played.
Organisers of the Rugby League World Cup said they had "received written assurances" that Friday's game between Australia v Scotland at the stadium would also go ahead as planned.
ACL said in a statement: "The arena is a profitable stand-alone business with huge potential and therefore is attracting strong interest from a number of parties.
"We have filed a notice of intention to appoint administrators and we will be aiming to use this period to complete a deal with a venue operator.
"It would also allow the arena to continue to generate funds and would also mean the Rugby League World Cup game and Coventry City fixtures will go ahead as planned, which is in everyone's interest."
You think something like this can't happen - Blackett
Wasps were founder members when the first national rugby union league was created in 1987 - and also when the professional era began in 1996, becoming the first champions.
And, in 20 years of Twickenham Premiership finals, they have lifted the trophy four times, including the first three.
Although they have a loyal, long-standing, still rather London-dominated fan base, their nomadic existence from Sudbury to Shepherds Bush to High Wycombe has not helped bring the crowds to Coventry that they hoped.
Their initial encouraging attendances, supplemented by ticket promotions, have fallen at a time when those of their stadium tenants Coventry City have been on the up.
After weeks of uncertainty and rumour about the club's future, head coach Lee Blackett, his players and the rest of the staff were told of their immediate fate at meetings held at both the CBS Arena and Wasps' training ground at Henley-in-Arden.
"A lot of people are really down," Blackett told BBC CWR. "You think that a club of this size that something like this can't happen, but unfortunately it has. And seeing the staff so upset is sickening.
"You realise it's not just the players and staff, it's the families behind them, their kids, their parents, everyone you see stood on the sidelines when you first go to watch a player.
"We've seen everything that has happened at Worcester - and we always hoped for positive news but this is the reality of it. The sad day has now come and, although things are ongoing and we now hope for some more positive news in the coming weeks, it's hard to see past this day right now.
"We've worked so hard as a group and it now looks like we'll be split up which is really sad. And the ones who've been brought up on Wasps - to lose that is absolutely gutting."
Wasps Holdings Limited in administration
Wasps Holdings Ltd is the holding company for Wasps Men, Wasps Women, Wasps Netball, the associated coaching and support teams, and the respective academies and pathways.
Andrew Sheridan and Raj Mittal, partners at specialist business advisory firm FRP, confirmed in a statement that Wasps Holdings Limited has ceased trading with immediate effect - and that they had been appointed as joint administrators.
"Regrettably, upon appointment the joint administrators were required to make 167 employees redundant, including all members of the playing squads and coaching staff," said the statement.
"A small number of employees have been retained to support with the orderly wind down of the company and the operation of the CBS Arena, which is unaffected by this administration and continues to trade as normal."
Joint administrator Sheridan said: "This is a dark day for English rugby.
"We know this will be devastating news for every Wasps player and member of staff, past players, sponsors, and their thousands of supporters throughout the world, and anyone who has ever been involved with this great club.
"Our immediate focus is on supporting those who have lost their jobs this morning. This will be an incredibly challenging time for every individual, and we will be assisting them in making claims to the redundancy payments service.
"The board and many others across the club have worked tirelessly over the last few weeks to try and find a solution that would allow the club to move forward, and it is with great regret that there has been insufficient time to allow this to happen.
"However, we remain in ongoing discussions with interested parties and are confident that a deal will be secured that will allow Wasps to continue."