MnD wrote:I'd guess the spikes are small retail investors entering "market" buy orders instead of entering limit orders around the mid-point of the bid-ask spread.
While that isn't the situation for this particular fund, it is a common phenomenon with low-volume ETFs. For example, look at the May 17 chart for EEMS:http://quote.morningstar.com/etf/chart. ... region=USA
Most of the morning trades were around $51.10, but someone probably placed a market order to sell and sold at $50.31.
The way to protect yourself against being on the wrong side of one of these trades is to use only limit orders for low-volume ETFs. If you place a market order to sell into a spread of $49.95-$50.05, but someone else accepts the $49.95 order before you place your order, you will sell at the next-best offer, which might be $49.93 but also might be $49.00. If you place a limit order to sell at $49.95 and the buy order at $49.95 is no longer there, you'll see what the new order is and can accept it or wait for other orders to arrive.