(Reuters) -Soroban Capital Partners has built a stake in industrial firm Johnson Controls International in the wake of pressure from Elliott Investment Management, Bloomberg News reported, citing people with knowledge of the matter.

A New York-based hedge fund, Soroban has invested more than $500 million, making it one of the company's top 20 shareholders, according to the report.

A day earlier, activist investor Elliott had taken a more than $1 billion position in the company, it had reported on Sunday, adding that Elliott's intentions could not immediately be learned.

Johnson Controls did not immediately respond to a Reuters request for comment. Soroban and Elliott declined to comment.

Shares of Johnson Controls were up about 0.4% in after the bell on Monday. The stock has gained nearly 20% this year, giving the company a market value of $46.5 billion as of Friday's close.

Founded in 1885, Johnson Controls makes a wide range of appliances and equipment for commercial buildings, as well as home comfort appliances. It provides electronic systems for offices, schools and hospitals in areas such as ventilation, security and fire detection.

The company has been attempting to divest its portfolio of heating and ventilation assets (HVAC) as part of efforts to streamline its business.

Robert Bosch GmbH, Lennox International and Samsung Electronics were among industrial firms competing to acquire the HVAC assets worth over $6 billion, Reuters had earlier reported.

Johnson Controls is also considering the sale of its ADT alarms business unit, which operates in Europe and Latin America, sources told Reuters earlier this month, adding the unit had already drawn interest from private equity funds.

The company earlier this month forecast third-quarter profit below Wall Street estimates, even as steady residential construction demand helped drive an earnings beat for the second quarter ended March 31.

Elliott, one of the world's most prominent investors, is known for pushing for changes at companies to boost shareholder returns. Some of its recent activist campaigns include at U.S. telecommunications infrastructure firm Crown Castle and oil refiner Phillips 66.