Greenfield: Latest buyout offer better than Quadrangle's

(Reuters) - Web-based marketing data company Greenfield Online Inc SRVY.O said a $17.50-per-share offer from an unnamed buyer was superior to a prior bid from media-focused U.S. buyout firm Quadrangle Group LLC.

Greenfield set Quadrangle a August 29 deadline to trump the offer, failing which Greenfield will be entitled to end the deal it made with the firm.

The company said the superior takeover offer was from a "Fortune 100 strategic buyer" and was not contingent on the receipt of financing.

In June, Greenfield said it would be bought by Quadrangle Group for $15.50 a share. Earlier this month the unnamed buyer bettered that offer by $2 a share.

Greenfield, which through its websites collects and sells consumer opinions to marketing research firms and end users, said if it terminates the merger deal, Quadrangle will be entitled to a $5 million fee.

Shares of Wilton, Connecticut-based Greenfield Online were up 7 percent at $17.16 in morning trade. They had touched their 52-week high of $17.44 on August 13.

(Reporting by Savio D'Souza in Bangalore; Editing by Himani Sarkar)