Notes from the desk.

How we measure a book, what the readings mean for a quote, and what venue teams on Robinhood Chain can design around. The figures inside run on live feeds.

22 SEPT 2026Toxic flow, measuredMakers do not fear volume. They fear being picked off by it. VPIN puts a number on that fear, and the number is computable from a public trade feed.FLOW QUALITY / HELM / 7 MIN
15 SEPT 2026Who quotes on Saturday?Robinhood Chain produces blocks through the weekend. The exchanges that list the underlying shares do not. That gap is a market design problem, and it has known answers.ROBINHOOD CHAIN / NAVIGATOR / 7 MIN
08 SEPT 2026Four numbers for a bookSpread, depth, entropy and imbalance describe most of what a trader needs to know about an order book. Here is how we compute them, and how each one gets gamed.FLOW QUALITY / HELM / 6 MIN