See what a trade would do to a portfolio's risk before making it. The measure is value at risk: the loss over one day that should be exceeded only one day in a hundred, which each portfolio must keep under 4% of its value.
This page sends the proposed trade to the desk as a private task. A worker of its own starts from the portfolio's live valuation (another worker's result), adds the trade at today's price, and works out the value at risk before and after, from how much each holding tends to swing: for bitcoin and ether, what the options market expects; for shares, how much they moved over the last 30 trading days. Nothing is traded and nothing is published. Stop, or leave the page, and the worker is removed.