The founder of activist investor TCS Capital Management rejected Angie's List Inc.'s board seat offer and continued to push for a combination with IAC/InterActiveCorp's HomeAdvisor.
In a letter to the Angie's List board, Eric Semler said the board seat offer "seems futile in light of the board's demand for onerous standstill provisions and its refusal to explore whether shareholder value can be maximized in a negotiated transaction."
An Angie's List spokeswoman said the company regrets that Mr. Semler declined to join the board.
"Of course our invitation came with the expectation that Mr. Semler would sign a customary standstill agreement," she said.
She also noted that the company's board and management "have been in discussions with all of our major shareholders and we have been listening to their feedback. We will continue to do what we believe is in the best interests of creating long-term value for all Angie's List shareholders."
Earlier this month, Angie's List said it wouldn't pursue an unsolicited buyout offer from IAC because it undervalued the company, which wants an opportunity to develop and enact a new growth plan before considering potential mergers.
IAC on Nov. 11 had made public a $512 million cash offer for Angie's List, in a proposed deal that would combine the services marketplace and consumer-review site with Internet brands such as About.com and Vimeo. IAC said it also was willing to consider combining Angie's List with its HomeAdvisor business through a stock-for-stock exchange.
In the letter Monday, Mr. Semler?who with TCS Capital holds a 10.7% stake in Angie's List?warned of ignoring IAC and shareholder demands for a sale in favor of making a "risky bet" on an "unformed" growth plan. He also said the board is being shortsighted in putting undue faith in its new LeadFeed product launched two weeks ago, which funnels Angie's List site visitors' service requests to service providers who can then reach out to customers directly.
"As a longtime shareholder of ANGI even before it was a public company, I can assure you that this is not the first time the board and senior management have become prematurely and unduly excited about a new product and plan, " Mr. Semler wrote in the letter.
Shares of Angie's List were recently up a penny at $10.77.
Write to Anne Steele at Anne.Steele@wsj.com