Quando il mercato è down, visioni di trading moderne
TD should do a refresher on how market exchanges work. In the meantime
- Flash to exchange your thousand orders a pico-second.
- Before exchange gets those orders in the book, send cancel orders
- Market begins to fill those orders, which end up vanishing as soon as they are posted
- Sudden stall of volume leads liquidity algos to notice the spread is starting to widen and they too start to flash and send up large order quotes
Do steps 1 to 4, loop.
While that is going on, (1 to 4) other exchanges are pushing volume, and see the large burst in exchange activity, so that price becomes the volume-price. Feeding on 4.
That continues until the links can no longer keep up with the large volumes of quotes/bids. Like a good old dns attack, something breaks. Usually a standard NYSE glitch comes down to a platform desynching from the global volume price and needs to step out of the market since the volumes of phantom quotes are so stupidly large vs. what network programs were designed (in UDP architecture) to process, based on the network protocol standards drafted in the 70's.
SO when the market breaks, a bunch of orders continue to be sent, but they never cross; so the most active (manually traded) dealers will move the price based on their own local books. This is done from your own price quotes, and as such may be wildily different than the global price, since manual traders do not have access to the central order book which includes the dark exchanges and speed switches.Which is why you see global drift, and then gravity engages once people get the master-book back online.
While that break happens, algos and speed traders can do whatever they want, since local exchanges are printing tickets which may very well be 10bps wide from where the real volume-price tape is crossing at. Theoretically taking advantage of this arb. is illegal, as a human, but many will buy when exchanges break/misprice.
Which is why one should never market-order when exchanges go down. And it's getting more frequent, which means liquidity algos are being taken manually offline due to risk and volatility limits pushing them out of the market. Like 89.