The Department of Justice has asked Six Flags and Cedar Fair for additional documentation regarding their planned merger.
In a Securities and Exchange Commission document filed Jan. 22, the companies said they both "received a request for additional information and documentary materials" from the DOJ as it reviews the merger. The companies plan to comply with the request by May 2.
The companies also said they still expect the merger to be completed in the first half of the year, subject to regulatory and stockholder approval.
Six Flags and Cedar Fair announced in November they planned a "merger of equals" to become a combined company valued at around $8 billion. The new company would operate under the Six Flags name.
That combined company would operate 27 amusement parks, 15 waterparks and nine resorts in the U.S., Canada and Mexico.
When the merger was announced, the companies called their market overlap "minimal."