The Pritzkers built an empire spanning hotels to manufacturing before agreeing two decades ago to split up their fortune among 11 descendants. Karen Pritzker, one of the heirs, has parlayed that wealth into venture capital, backing firms such as Snap Inc. and Spotify Technology. Now she’s joined the wave of investors turning to blank-check firms. The Pritzker Vlock Family Office is the anchor investor for Thimble Point Acquisition Corp., a special purpose acquisition company that raised almost $300 million in an initial public offering in February.