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518 points bwfan123 | 1 comments | | HN request time: 0.207s | source
1. mdnahas ◴[] No.44493016[source]
I was a quantitative trader for an options trading firm in the early 2010s. We were a very technical firms and hedges options trades within minutes. So, a trade with us would shift the stock price quickly. Even with that, we got scammed by traders doing this kind of thing on single stocks. My boss said that he complained to the broker and SEC, but nothing happened. We wrote code to limit our losses from this kind of scam.

We were probably able to find it because we did hedge quickly. Hedging costs money (trading fees, 1/2 spread) so some firms did it less often. We heard that Bear-Sterns only did it 1 time per day (around 4pm when spreads were small and over-night movement risk was nigh). They wouldn’t have caught this scam.