There is the persistent narrative that the Securities Information Processor (SIP) is a dysfunctional public road, costing investors much more than the proprietary autobahns fast traders get to use.

WASHINGTON — This isn’t your grandma’s sewing circle. “We start off with a glass of wine,” says Cecily Habimana, half of the team behind the Sip and Sew DC series at Mount Rainier Artist Lofts in ...