Twitter Inc said on Friday that the waiting period under the HSR Act for Elon Musk's $44-billion acquisition of the social media firm has expired. according to ndtv.com that quoted Reuters.

Twitter added, "Completion of the deal is now subject to remaining customary closing conditions, including approval by Twitter stockholders and the receipt of applicable regulatory approvals."

As per the the HSR Act, or the Hart-Scott-Rodino Antitrust Improvements Act of 1976, parties are supposed to report large transactions to both the Federal Trade Commission and the U.S. Department of Justice Antitrust Division for review.