(Bloomberg) -- Tokyo Gas Co.’s shares jumped as much as 15% after Elliott Investment Management said it now held a major stake in the company and may make “important proposals” to the utility.

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The fund has acquired 5.03% of Tokyo Gas, it said in a filing to Japan’s finance ministry on Tuesday. The activist investor believes the company should sell properties and real estate projects, including the Park Hyatt Tokyo hotel, that could be worth as much as 1.5 trillion yen ($9.7 billion) combined, according to a person familiar with the matter.

The surge in the share price was the most on an intraday basis since 1987. The stock was trading up 12% at 4,291 yen as of 10:53 a.m. in Tokyo.

Activist funds have been campaigning to unlock hidden value in Japanese companies. Elliott has built stakes in Sumitomo Corp., SoftBank Group Corp. and real estate developer Mitsui Fudosan Co. this year, but this is the first time its bought more than 5% of one of the country’s companies since 2019.

Tokyo Gas is Japan’s biggest provider of the fossil fuel, with around 30% of the domestic market. The company produces and imports liquefied natural gas, and has a retail power business. It also has sprawling overseas assets including investments in an offshore wind fund and a US shale gas subsidiary.

But for Elliott, the focus is on Tokyo Gas’ property portfolio. The investor is of the view the company can improve its capital efficiency by selling a lot of its real estate, according to the person familiar. That’s in line with a tactic utilized by activist investors in Japan, who see a huge gap between the book value of real estate assets and what they actually cost on the current market.

“It’s a legitimate point to ask the company to boost its corporate value by investing in its core business and buying back shares,” said Naoki Fujiwara, a senior fund manager at Shinkin Asset Management Co. “It’s fine to hold onto some properties for data centers, but the company doesn’t need office buildings and real estate for lease.”

Tokyo Gas has made real estate development a key part of its current midterm management plan, saying it will bolster its “ESG-oriented” development. The firm’s subsidiary, Tokyo Gas Real Estate Co., has been managing the properties and assets the firm owns for more than 70 years, and has been working to build a virtually carbon emissions-free town near Tokyo’s main fish market.