LONDON  - TUI, the world's largest tourism company, lost 1.1 billion euros ($1.3 billion) after COVID-19 wiped out revenue in the three months through June and said it was evaluating its options to achieve an optimal balance sheet structure.

The company, which secured a second credit line from the German government on Wednesday, said on Thursday it resumed holidays in mid-June and demand had returned, helping to strengthen its strained finances.

TUI said liquidity now stood at 2.4 billion euros, which gave it confidence it could make it through to 2021 as the pandemic continues to hit travel and as it approaches the winter season when holiday companies generally lose money.

Chief Executive Fritz Joussen told reporters that he did not know yet whether TUI would need the extra credit line but the company wanted to be prepared for the worst case scenario.

TUI shares listed in London, which have lost 60% of their value this year, were down 1% at 364 pence.

Having already agreed a 1.8 billion euro state-backed loan in April, the company said it was evaluating options to achieve the optimal balance sheet structure, without providing further details and expected normality to return in 2022.

"We think plans to reduce leverage in 2021 and reach normalised profit growth in 2022 are ambitious," said Jefferies in a note.

TUI's made a quarterly underlying operating loss (earnings before interest and tax) of 1.1 billion euros as revenues plummeted 98.5% to 72 million euros compared with a profit of 102.3 million euros in the same period last year.

The company said it was making progress with the cost cuts needed to help it withstand the crisis. It warned in May that it would need to axe 8,000 jobs and save 300 million euros a year.

The pandemic continues to wreak havoc on the travel industry. Hopes for a strong summer recovery were dashed by new restrictions brought in by Britain on travel to Spain, meaning TUI had to cancel more holidays.

TUI said bookings for the current summer period are down 81% from last year though next summer looked promising with bookings up 145%. ($1 = 0.8460 euros)

(Reporting by Sarah Young; Additional reporting by Klaus Lauer; Editing by Paul Sandle, James Davey and David Clarke) ((sarah.young@thomsonreuters.com; +44 20 7542 1109; Reuters Messaging: sarah.young.thomsonreuters@reuters.net))