By Ben Otto

Shares of Thai hospitality company Minor International rose sharply Tuesday on plans to raise 25 billion baht ($781.0 million) to strengthen its balance sheet amid the economic stresses of the Covid-19 pandemic.

Bangkok-based Minor, which operates brands including Marriott, Four Seasons and St. Regis in more than 50 countries, rose 9.5% to THB18.40 in morning trade, paring year-to-date losses to 49%.

Minor on Monday said it would raise THB10 billion via an issuance of perpetual bonds and THB10 billion via a rights offer in the third quarter. Following the rights offer, the company plans to raise the final THB5 billion via three-year warrants.

The company described the fundraising as a "proactive approach" to ensure its ability to service obligations and maintain a healthy balance sheet amid slowing business activity caused by the Covid-19 crisis.

Minor has been hard hit by global lockdowns and movement restrictions designed to stem the spread of the coronavirus, posting a first-quarter net loss of THB1.77 billion. It said Monday that second-quarter results would be further affected by the temporary closure of hotels and dine-in restaurants.

Dillip Rajakarier, group CEO, said Minor expected full support from major shareholders for the transactions. The company estimates its interest-bearing debt-to-equity ratio to decline to 1.3x by the end of the year, he said.

Write to Ben Otto at ben.otto@wsj.com