SB Energy offered OpenAI a major perk to land it as a data-center tenant ahead of the SoftBank-backed company’s initial public offering.

OpenAI was issued warrants worth an estimated $5.5 billion in SB Energy—a company it previously invested in, according to draft IPO documents reviewed by The Wall Street Journal.

SB Energy is expected to make its IPO filing public as soon as this week. The company, which is majority-owned by Masayoshi Son’s SoftBank, is working with bankers on an IPO as soon as next month, aiming to raise between $5 billion and $7 billion, the Journal has reported. The terms aren’t yet final and could change.

The draft IPO documents provide the first detailed look at the financial ties between SB Energy and the companies supporting its ambitious expansion into AI infrastructure, namely parent company SoftBank and OpenAI. They also illustrate the interconnectedness of major AI players that has come to define the boom.

SB Energy’s base of data center customers currently consists of firms that are also its investors.