The Korean Teachers’ Credit Union recently bought a minority stake in 51 Astor Place, a deal that values the futuristic-looking Midtown South office property at $600 million.

The Seoul-based credit union, which has more than $23 billion in assets under management, paid roughly $113 million to buy a 49-percent stake in the fully leased, 400,000-square-foot building.

“We’ve already invested in a couple of deals” with Minskoff Equities, said James Yoohoon Jeon of FG Asset Management, the Korean firm that oversees the credit union’s investments in 51 Astor and 101 Sixth Avenue, another Minskoff property which it bought into in 2013.

“We believe there’s a huge potential for rent increase in Midtown South,” Jeon added. KTCU recently partnered with TIAA-CREF to purchase a $175 million loan on David Werner’s Socony-Mobil Building, the first investment in what the partners said will be a $1 billion joint venture.

With IBM’s expansion to roughly 150,000 square feet earlier this year, Minskoff’s Fumihiko Maki-designed office building hit full occupancy, Minskoff achieved records rents for the area, with financial firms Claren Road Asset Management and Tudor Investment Corporation agreeing to pay triple-digit rents.