If you look at a daily chart or any other records, like on nasdaq’s site, sometimes you see a huge jump (10%+ and then back down again. Who are typically on either of the sides of those trades? Some retail guy who screwed up?
My phone call carries great weight in after-hours trading. Just saying.
Low liquidity in after hours. Some folks might get confused since it is limit order only and the bid ask spread jumps in afterhours.(they think they are putting in a market order for the price as close) Also, the dark pool trades of the day are factored in after close
But also let’s not forget those phone calls.
“Limit order only”?
why are you perplexed?
^what is limit order only?
really? as in usually you have a choice between “market” “limit” “stop”. The market order puts you in at best price possible at the time (theoretically, the HFT eat these for lunch). Many novice participants just use market orders to buy or sell equities. Market order is often the default setting so they just push buy and send with out paying attention. In extended hours you can only place limit orders so when the person goes to “buy” and 'send" they did not realise they just put in a limit buy order 20 cents over the market.
Are you suggesting that market orders don’t exist in after hours trading or just that your broker does not allow you to place them online for the extended session? Haven’t checked recently, but most after hours trading back in 2013 was institutional.
I’m pretty sure that it is the standard on most retail trading platforms, which is enough to support the situation I was talking about.
I foresee a KMD v. Ghibli battle to the death occuring soon
That wouldn’t even be a fair fight, dude would get disintegrated.
On topic, I’ve seen these also, they are pretty darn big, and am not certain the question has been answered why these are happening? Is it someone buying huge, and so their final unit has a high cost (creating the spike), but their avg cost is reasonable? I’ve had orders in when these spikes happen, but I don’t get filled.
Maybe it’s something like that, which would explain why the prices aren’t tradable.
Ghibli… *truce*.
Not only is it common knowledge that the “limit order only” situation fouls up some novice trader’s day. I have personal experience with the matter…
****** from the thread on the worst trade you ever made********
It was when I first was experimenting with extended hours trades. I saw that sometimes you could get fills at rediculously low prices if you just put in the limit order and see what happens. I meant to put in a trade down about .30 (it was only a $2 stock.) I was not used to the large bid ask spread in extended hours so when I brought up the trade box I was just looking at the cents parts. I did not realize it was a whole dollar above the market! I placed the trade and of course it got filled right away………and my account was also immediatly down about $300! My trade was so stupid that it was memorialized on the the 6month 4 hours chart for all to see 
Makes sense, thanks for sharing
You should frame that chart!
There are millions of market participants, so that would make sense – fairly frequently we see a weird trade way out of line, but we don’t get filled because there’s no volume. Alright, I’m going with that answer for now.
I was hoping that someone might post that has more knowledge than me on the subject, but it doesn’t look like that is going to happen. My experience trading extended hours is dated, but I’ll share what I knew to be true at the time(it’s cruel that I see a vision of HRC every time I hear “at the time”). It’s all fairly elementary.
Extended hours trading came to prominence in the late '90s, but never found the growth and popularity that was expected. The volumes have stayed anemic and order books are shallow. Our resident stripper’s(I say that affectionately and in hopes some will send business her way) theory while possible and popular, and probably has happened, is not likely to explain large moves away from the market. Most platforms warn the trader when a limit order is attempted to be placed way out of current market, even if limits are set at ask and bids by default. Most brokers do restrict after hours online retail orders to limit orders, but some will allow market orders if you call it in. The presence of market orders when the order book dries up explains the large disconnects. Institutions will have their traders set algorithms to throw small market orders every minute or second, or whatever, in hopes of unloading or adding a position…Oh, and the reason for the online limit order restriction is that the brokers had to field complaints when their clients had no idea what they were doing and wanted the trade reversed. Just easier to shut it down. The same issues arise in thinly traded issues during regular trading hours. Order books can even dry up in highly traded issues. Trader beware. I would be surprised if these disconnects didn’t always involve a market order, placed by a pro or amateur. Things may have changed, but this is my recollection. If market orders are now not allowed by anyone, that’s news to me.
Here’s a freindly warning from the SEC:
" Competition with Professional Traders. Many of the after-hours traders are professionals with large institutions, such as mutual funds, who may have access to more information than individual investors."
And I’ll add, they really know how this shit works.
If algorithms were set up to to unload positions by throwing out market orders in extended hours they would just be setting themselves up to get fished by ME with my limit buy under the market. Why would anyone use market orders in low liquidity… especially institutions. I suppose it could work if the algorithm was set to only buy under the market or sell over the market. …oh wait… that’s called a limit order. 
Either way, most likely at least one side of the extended hours trade is a limit order. Both side probably aren’t dumb.
Too funny…They’re acting on what they see as “privilaged” information and want in or out before normal hours. They are throwing a small order EVERY second or minute or whatever until their relatively enormous position is traded. They are hoping to minimize their market effect. This happens during regular hours as well. Many still do trade for investment purposes and move markets. The primary interest is clearing the trade. Certainly no interest in scalping. This is all besides the point anyway. The point is that there are market orders during extended sessions that are more likely to explain these disconnects. Might surprise some people, but some market participants are paid to know more than the people sitting at home in their underwear. Market makers(professional scalpers) historically maintain order and their software see everything, It seems they adjust before I can confirm my order was accepted, milliseconds. HFTs operate similarly but with no mandate to maintain order and will abandon at will. I imagine a lot of extended hours are just the wild west, no sheriff maintaining order.
Ok… so you insist there are market orders being placed in extended hours. So I can put in limit orders to buy 10% below the market or sell 10% above it and scalp these guys, yes? Why not?
also, if HFT is at work, they can only front run market orders. Limit orders are safe… so again, why would anyone in their right mind use maket orders in extended hours?
^Same reason they do during regular hours. Execution is more important than price for that order. Nothing particular unique about extended sessions, except the much lower volume and liquidity overall. More easily manipulated. Some securities during normal hours have anemic markets as well. Same concerns. And some after hours markets are quite liquid. HFTs certainly try to take advantage of those prioritizing execution by sniffing out the large order. "Pinging " is the common technique. So how does your latency compare to those co-locating their servers? Here’s a nice article- http://www.zerohedge.com/news/2013-06-11/hft-stock-manipulation-action And from the comments section- RebelDevil gatorengineer Jun 12, 2013 12:04 AM Exactly. Day-Trading for the non-HFT is dead. The only chance you have of winning in stocks now is “investing” (either BTFD and/or STFR and holding the position).