With headquarters in the South Korean capital of Seoul, Media Research Inc is best known for its public opinion polling, which last year tracked the Korean National Assembly elections and previous presidential polls.
MRI's chairman Koo-Ho Chung, a former press secretary to retired South Korean president Doowhan Chun, will continue to manage MRI and will report to Millward Brown's regional Asia Pacific office in Singapore.
"The combination of our talent and our Korean market expertise with Millward Brown's brand-building tools and global resources makes for a strong consultancy formula -- the best of local working with the best of global," Chung said.
The Korean market is seen as increasingly important to marketing services firms and has been the subject of several major international pitches recently, including Samsung's $700m global account.
The bulk of that business went to a group of WPP agencies operating as Team Samsung, including Millward Brown sister research firm Research International.
Andreas Sperling, chief executive of Millward Brown Asia Pacific, said: "Korea is an escalating priority for our clients. In addition to being one of the big four economies in the Asia Pacific region, Korea is increasingly the home to a whole range of global brands such as Samsung, LG and Hyundai.
"Korea is therefore at the top of our expansion strategy and we are delighted to partner with the talents of MRI."
The new company will be known as Millward Brown Media Research Inc.
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