> Of all the retail investing platforms, I think they are the biggest and the top pick for rather serious investors. I would agree with this, but I'm not sure

> Of all the retail investing platforms, I think they are the biggest and the top pick for rather serious investors. I would agree with this, but I'm not sure that this is a meaningful universe for comparison. It's also quite different from the original claim with which I disagreed. > use a professional broker such as Interactive Brokers, which institutional clients use I'm sure that there are some institutional customers who use IBKR, but it's probably not many and they're probably not very cost sensitive. This is also why I added so many qualifiers to my disagreement. You can open an LLC and be an institutional customer in a certain sense, but it doesn't mean that you're cost sensitive and trying to cut your costs to the bare minimum.