> Another HFT programmer here. I once had to make a run-time modification to an algorithm to keep about $100 million from going at a lower price than what the traders wanted. Sometimes market conditions change so fast that the traders demand the ability to make rapid adjustments to the algorithm. They're willing to take the risk. They can't wait for the safe development cycle.

Someone should post this next time the issue of "TDD and sudoku-solvers" comes up on HN.