SK Square, the investment arm of SK Group, has completed the process of selling a portion of its stake in its security service subsidiary SK Shieldus to EQT Partners, a private equity fund operated by Sweden's largest conglomerate, the Wallenberg Group, a filing showed Thursday.

SK Square said it has sold 28.82 percent of its stake in Korea Security Holdings, the parent firm of SK Shieldus, for about 860 billion won ($684 million).

EQT Partners acquired a 36.9 percent stake in SK Square and a Macquarie Asset Management-led consortium for about 2 trillion won. The Swedish private equity fund will issue 200 billion won of new shares of Korea Security Holdings on Friday, according to SK Square officials.

The issuance of new shares by EQT Partners will be used as a source of finance for SK Shieldus' new business, according to a prior agreement between SK Square and the private equity firm.

Upon the deal, EQT Partners will become the largest shareholder of Korea Security Holdings with a 68 percent stake, while SK Square becomes the second-largest shareholder with a 32 percent stake. SK Square and Macquarie Asset Consortium previously held 63.1 percent and 36.9 percent of SK Shieldus’ parent firm, respectively.

Of the 860 billion won in proceeds from SK Square’s stake sale, 410 billion won was deposited Thursday and the remainder of the funds will be received within two years as a loan to EQT Partners.

SK Shieldus’ new executives and board of directors will be chosen through the company’s internal procedures.

SK Square said the latest deal was its first large-scale investment achievement since its launch as an investment arm after being split from SK Telecom in November 2021. The company has more than 20 companies, including SK Hynix, in its investing portfolio.

At a hotel in Barcelona, Spain, in February, SK Square Vice Chairman and CEO Park Jung-ho announced EQT Partners’ acquisition of SK Shieldus’ shares and plans for the two sides’ joint management.

At that time, the vice chairman said, “For the future growth of SK Shieldus, we will cooperate with EQT Partners to develop strategies for further growth in Korea and global expansion at the same time.”

SK Square is also reviewing a plan to return 200 billion won to shareholders depending on its investment performance from SK Shieldus.

“Under the goal of continuously increasing the corporate value of SK Square and our portfolio companies, we will show meaningful results to shareholders in the second half of this year,” said SK Square CEO Park Sung-ha.