What exchanges offer trail orders? Trail orders are extremely useful, much more so than simple stop loss orders. Are there any exchanges that offer trail orders?

Using a trail order, the stop price would track the market price as long as it goes in the same direction, but not if the market price moves in the opposite direction. For example, say BTC is bid 250 USD and I place a trail stop (sell) order for 10 USD below the bid price. Here's what happens if BTC moves:


start => my trail order will have a stop of 240
BTC bid 260 => my trail order will have a stop of 250 now
BTC bid 265 => stop 255
BTC bid back to 262 => stop 255 stays in place
BTC bid 268 => stop 258
BTC bid 263 => stop stays 258
BTC bid tunnels down to 255 => market SELL order triggered as soon as the bid went &lt;=258


As of June 2013, Tradehill does not offer stop orders.
This answer needs an update. As of 2017, the following exchanges support trailing stop orders:


Kraken - fees up to 0.16% - 0.26%
Bitfinex - fess up to 0.10% - 0.20%
Bitstamp - fees up to 0.25%


However, there's an important warning to be heeded: by placing trailing stop orders with any exchange, you expose yourself to very short-lived price spikes that are not reflected anywhere else. Here is a screenshot from Kraken where the three red dots represent trades triggered by the price falling by 25% for a minute, only to shoot back up immediately afterwards. The trailing stop didn't offer any protection here; on the contrary, it caused a loss.