This usually means retail flow( regular folks) using E-Trade, Ameritrade, Interactive Broker, Scott Trade, etc to buy/sell shares. These firms get paid to send their orders to HFT firms who fill the orders internally(ie not on an exchange) and then use trade reporting facilities to notify the markets of these orders.
Also supporting this thesis is the number of small and odd lot trades.
So you could argue that main street likes Square more than Wall street.
With the market down and Match.com's IPO popping less, this is a very good opening for them.
Having said that, the real test for most new stocks is 6 months out when they've had 2 reporting quarters, options start to trade and short interest numbers( a measure of how many people want to short the company) start to have some validity.
Question to anyone more informed than me......
Do squares late series investor's liquidation preference kick in at the IPO opening price or the vwap price through the day?
If it's the former, then the late stage investors are going to get a great double dip of getting a huge increase in shares due to the ipo price being below their strike and get the benefit of this pop.
Maybe late stage investors aren't as dumb as people around here have been claiming lately?