The tie-up could be reached as early as this month, the Journal reported, citing people familiar with the matter.
Shares of CF Industries, which has a market value of about $14.8 billion, were up 7.4 percent at $67.22 after the report.
Both CF Industries and OCI were not immediately available to comment on the report.(on.wsj.com/1REe7bJ)
The terms of the deal the two companies are discussing are unclear, and a transaction may not materialize, the WSJ said.
The deal may be structured as a so-called inversion — a type of combination in which CF Industries moves its tax headquarters abroad, the Journal said.
OCI’s market capitalization was $5.5 billion euros ($5.5 billion) based on the company’s outstanding shares as of Dec. 30.
Reporting by Sneha Banerjee in Bengaluru; Editing by Maju Samuel