Activist investment firm Jana Partners said on Tuesday it had urged Zendesk Inc (ZEN.N) to abandon a deal to buy Momentive Global Inc (MNTV.O), the parent of online survey portal SurveyMonkey. Zendesk agreed in late October to buy Momentive in an all-stock deal, which at the time was valued at nearly $4 billion. read more Jana urged Zendesk's board to terminate the acquisition now rather than wait months for a shareholder vote to clear the deal that appeared likely to fail. "We believe Zendesk is highly undervalued and has far more attractive opportunities to create shareholder value than by acquiring Momentive," Jana said in a letter sent to the software firm's board.Jana did not disclose the size of its stake in Zendesk, but said it was a significant shareholder. Zendesk and Momentive did not respond to Reuters' requests for comment. Jana has built a reputation for working collaboratively and behind the scenes with target companies since Barry Rosenstein founded the firm two decades ago. Zendesk shares were up 7.2% in afternoon trading, while Momentive Global shares were down 3.2%. Zendesk, a customer service software vendor, has seen a surge in business during the pandemic as its enterprise customers accelerate digital transformation. Reporting by Eva Mathews in Bengaluru; Editing by Ramakrishnan M. and Anil D'Silva