Jason Pressman spent last Thursday morning cheering from the balcony of the New York Stock Exchange as shares of San Mateo software firm Zuora, which he backed in 2008, began trading. By the market’s close, Zuora’s stock had soared 43 percent, making his venture capital firm’s $17 million investment in the company worth roughly $150 million. “Not bad at all,” Pressman said by phone last Thursday night, before heading to a celebratory dinner with about 60 people at a pricey Italian restaurant in the Chelsea section of Manhattan.