After a historically slow period for tech IPOs, investors are getting read for debuts from Arm, Instacart and Klaviyo. : It's been 20 months since a notable venture-backed tech company went public in the U.S., and the chatter in Silicon Valley has centered around who will break the ice. On Friday, grocery delivery startup Instacart and data and marketing automation company Klaviyo filed for stock market debuts. Earlier in the week, chip designer Arm, which is owned by Japan's SoftBank, said it plans to hit the Nasdaq seven years after being taken private in a $32 billion acquisition.