Growth in the number of patent assertions facing startup companies is hampering U.S. venture capital, according to a new survey of venture capitalists (VC) and venture-backed companies from the National Venture Capital Association (NVCA) and Robin Feldman, director of the Institute for Innovation Law at University of California Hastings. Eighty percent of VC respondents note that the number of patent assertions filed against portfolio companies have increased over the past five years, with half indicating these assertions were a major deterrent to investment.