EasyJet and Carnival Corportion are expected to drop out of the FTSE 100 index of top companies after heavy share price falls due to Covid-19.
Prices have fallen 34% and 53% respectively in the past three months.
Nicholas Hyett, of fund shop Hargreaves Lansdown, said easyJet and Carnival have struggled because travel restrictions meant revenues sunk to practically zero.
But cruise ships and aircraft are expensive and often funded by debt, so costs remain high.
He told The Telegraph: “That’s a toxic combination for profits and could leave both companies lumbered with large quantities of debt that will take years to repay.
“Even when the immediate crisis is over it’s doubtful whether demand will return to where it once was.”
Next Wednesday could see the biggest reshuffle in the FTSE 100 list of biggest companies since the 2008 financial crisis, analysts say.
Helal Miah, investment research analyst at the Share Centre, said: “This reshuffle looks set to be one of the biggest in many years. We expect a minimum of four in, four out – but depending on market moves we could see more.”
He added that P&O Cruises and Cunard owner Carnival Corporation was the “clearest candidate” to be relegated.