(Corrects headline to say Helios plans to list some assets, not itself, in the U.S.; corrects paragraph 1 to say Helios plans to merge some of its assets, not itself, with Onyx; removes Oando stake reference in paragraph 2; corrects paragraph 3 to say deal expected to close in H2 of 2023, not next year)

Jan 18 (Reuters) - Private equity firm Helios Investment Partners plans to merge some of its assets with Onyx Acquisition Co I in a deal valued at nearly $1 billion, including debt, the blank-check firm said on Wednesday.

Founded in 2004, the Africa-focused firm manages $3.6 billion of funds.

The deal, expected to close in the second half of 2023, will create a publicly listed energy transition infrastructure platform, Helios Energy Transition Infrastructure (HETI), focused on the development of natural gas and low-carbon energy infrastructure businesses and assets in Africa.

Helios is pushing ahead with its plans at a time few are. Rampant inflation, aggressive interest rake hikes and the fallout from the Russia-Ukraine war led investors to shun speculative investments like special purpose acquisition companies (SPACs).

A record number of companies opted for SPACs over traditional initial public offerings in 2021. But regulatory concerns and heightened scrutiny seems to have cooled down Wall Street's hottest investment trend, with majority of SPACs trading below their offering prices.

Still energy companies fared better, with Greenfire Resources Inc, X-energy and NET Power filing to go public in the last few months.

A SPAC typically sells shares at $10 apiece, puts the cash in a trust account, and then searches for a company to buy. Its shareholders can choose to redeem their shares in return for cash. (Reporting by Mehnaz Yasmin in Bengaluru; Editing by Maju Samuel)