New York—Nielsen Co. has agreed to acquire the remaining shares of word-of-mouth tracking company BuzzMetrics. Nielsen already owns 58% of BuzzMetrics. Financial terms were not disclosed for the latest deal, which is expected to be completed by the end of the month. The buyout follows a similar move Nielsen made to acquire the remaining 40% of NetRatings that it doesn’t already own. That deal is expected to be completed by the end of the second quarter.