Robinhood announced this morning that it has raised $200 million more at a new, higher $11.2 billion valuation. The new capital came as a surprise. Astute observers of all things fintech will recall that Robinhood, a popular stock trading service, has raised capital multiple times this year, including an initial $280 million round at an $8.3 billion valuation, and a later $320 million addition that brought its valuation to $8.6 billion. The Exchange explores startups, markets and money. You can read it every morning on Extra Crunch, or get The…