NxStage Medical Inc. and Fresenius Medical Care Holdings Inc. have each received a request for additional information from the U.S. Federal Trade Commission regarding Fresenius’ proposed acquisition of NxStage, according to an SEC filing. The request extends the waiting period required by the Hart Scott Rodino (HSR)Act until 30 days after both companies comply to the request.

The HSR Act requires that parties to certain mergers and acquisitions submit premerger notification filings and wait before consummating the transaction. The waiting period is normally 30 days.

NxStage entered an agreement on Aug. 7 with Fresenius Medical Care to merge with the dialysis provider and manufacturer. NxStage would remain as a wholly-owned subsidiary of Fresenius, according to a proxy statement released by NxStage.

If shareholders approve the sale, they would receive $30 per share in cash. The payment represents a premium of approximately 30% over NxStage’s closing share price on Aug. 4, the last trading day prior to the public announcement of the merger. The cost to Fresenius, if the merger is approved, is approximately $2 billion.

NxStage shareholders will have an opportunity on Oct. 27 to weigh in on the buyout offer from Fresenius Medical Care.