Some of Britain's biggest business names face relegation from the FTSE 100 after the Covid-19 pandemic sent their shares plunging.
British Gas owner Centrica, Easyjet and ITV could all lose their blue-chip status in this month's reshuffle. Others threatened are cruise company Carnival and aerospace and defence group Meggitt.
The quarterly reshuffle will be based on tomorrow's closing values. Companies in line for promotion from the FTSE 250 index include cyber security group Avast, Ladbrokes owner GVC, emergency repairs firm Homeserve and medical device company Convatec.
Grounded: Struggling Easyjet could lose its blue-chip status in this month's reshuffle
It could be the biggest shake-up since the financial crisis, reflecting huge share price moves during the virus crisis.
Russ Mould, investment director at AJ Bell, said: 'The Covid-19 crisis has had a devastating impact on many companies and has been a help to very few. The next quarterly reshuffle looks like it will be one of the biggest in 20 years.
'Attention is starting to turn to recovery so we'll start to see which companies can emerge most successfully.' FTSE Russell, which is owned by the London Stock Exchange, reviews the membership of its indices every three months, reshuffling companies based on changes in share prices.
Admission to or relegation from the FTSE 100 is significant. Companies in the Footsie have their shares snapped up by tracker funds, and the list is seen as a safe harbour for pension fund cash.
For Centrica, dropping out will be a particularly bitter blow. The company has been part of the index in one form or another since British Gas was first privatised in 1986.
Its 600,000 small shareholders saw the value of their stock plummet by 86 per cent under former boss Iain Conn. He left in March and has been replaced by Chris O'Shea. Marks & Spencer, another Footsie stalwart, suffered the same fate as Centrica last year, having been a member since the index was founded in 1984.
The last FTSE 100 review was in March, before the virus crisis began to bite. Drugs giant Astrazeneca has proved to be one winner of the crisis, becoming Britain's most valuable company – worth £117billion.
Nicholas Hyett, at Hargreaves Lansdown, said British equity was more than 10 per cent higher in March. He added: 'The world has changed since the last review.'