MediaTek's proposed merger with MStar Semiconductor has not obtained regulatory approvals by the antitrust authorities in China and Korea, and therefore will be completed at a later date, according to the two Taiwan-based IC design houses.

The time frame for completion of the pair's merger has been revised to May 1, 2013, from the originally-scheduled January. Following the announcement, MStar's shares fell the daily 7% limit to close at NT$231.50 (US$8) on the Taiwan Stock Exchange (TSE) on December 6.

MediaTek reiterated the goal of merging with MStar, which MediaTek sees a milestone for its business.

MediaTek in mid-2012 announced plans to execute a tender offer to buy a portion of MStar shares, and a follow-up merger with the fellow IC design company. MediaTek has completed the tender offer, meeting the requirements to proceed with the merger deal reached with MStar.