It was only a couple of weeks in, when I had to react within 60 seconds (USDJPY option expiry, NYC cut) on a position our front book would have lost MM on; with senior sales MDs screaming at me as well. Lo and behold, I was just used to it and could focus and execute based on my training.

My wife calls my thinking on the training - Stockholm syndrome. I still believe those skills were incredibly valuable for me, just perhaps delivered in a more 2021 acceptable approach.

Took many more years for us to understand that we had learned more about banking and making money than our masters had learned about the potential uses of the platforms we had built.

We started Sandbox Banking. Many of our friends are at hedge-funds :-(. What's the career paths of those that first built sec-db?

Agree with you that HFT performance is not correlated with market direction. But given the volume of trades it would imply that many of the trades are occurring on a smaller pool of equity instruments. I'd think that given liquidity constraints and competition that there's a sweet spot in terms of number of stocks that a given strategy is actually efficient on.

So not entirely sure why we consider every trade to be iid - rapid shocks (flash crash), equity specific news etc would affect a number of trades at once changing the 51% probability?

Also does anyone know if the profitability numbers include payments to be a market-maker?

At a push, I'd go with - Investing in stocks:Vanguard :: Investing in companies : Random funds that will only invest if you have a brand-name lead investor

I'd defer to Paul's point that choosing a too high (or non-existent) cap makes no sense. We did have to negotiate our cap and we set it so that we had a realistic shot of hitting 2-3x that in Series A pre money which in my mind is why an angel should be investing. I'd personally consider it a disappointing outcome if I raised at my cap and I'd hope my investors would as well.

A cap is not a valuation and I agree that everyone thinking it is, is a problem.

The biggest benefits of the note structure to us were a) Rolling close b) Not wasting time debating "valuation" when neither us nor the angels were capable of estimating a number with limited to no data.

The point about SOAP not requiring documentation makes no sense either. You'd still need to document what the underlying fields in the various endpoints are. (We build against a lot of terribly documented SOAP APIs and its pure torture)

In terms of PUT (and PATCH) not being extensively used - it comes down to your use case. For the idempotent micro-services we build APIs against, there is a massive difference in the behavior expected for POST/PUT/PATCH and it would be pretty burdensome (and limiting) to have to create parsing code on the server for POST.