A stop order won't be automatically fired in after-hours trading?
Stop orders and stop limit orders typically do not execute during extended hours after the general market session has closed. Stop orders are market orders and market orders especially are not executed during extended hours. Although there are exceptions because a broker can say one thing and do another thing with the way order types are presented to customers vs what their programming actually does. The regulatory burden is a slap on the wrist, so you need to ask the broker what their practices are. Orders created during normal market hours do not execute in extended sessions, different orders would have to be made during the extended session. Your stop order should execute if the normal market hour price stays below your stop price. So a stop limit would actually be worse here, because a stop limit will create a limit order which may never get hit (since it is above the best bid best ask)
The simplest solution to fire-and-forget is to pick something like a Target Date mutual fund made up of low-overhead index funds (within your 401k or a Roth IRA, perhaps) and set up automatic purchase to that.  If you're talking about limit orders and so on, that ain't simple. A stop-loss order becomes a market order when a trade has occurred at or below the trigger price you set when creating the order. This means that you could possibly end up selling some or all of your position at a price lower than your trigger price. For relatively illiquid securities your order may be split into transactions with several buyers at different prices and you could see a significant drop in price between the first part of the order and the last few shares. To mitigate this, brokers also offer a stop-limit order, where you set not only a trigger price, but also a minimum price that you are will to accept for your shares. This reduces the risk of selling at rock bottom prices, especially if you are selling a very large position. However, in the case of a flash crash where other sellers are driving the price below your limit, that part of your order may never execute and you could end up being stuck with a whole lot of shares that are worth less than both your stop loss trigger and limit price. For securities that are liquid and not very volatile, either option is a pretty safe way to cut your losses. For securities that are illiquid and/or very volatile a stop-limit order will prevent you from cashing out at bottom dollar and giving away a bargain to lurkers hanging out at the bottom of the market, but you may end up stuck with shares you don't want for longer than originally planned. It's up to you to decide which kind of risk you prefer. You would have to compare your backtesting to what you will be doing in real trading, and try to have the backtesting as close to your real trading as possible. Note: you may never get the backtesting to match your real trading exactly but you need to get as close as possible. The whole purpose of backtesting is to check if your trading strategies - your signals, entries and exits, and your stops - are profitable over various market conditions. As you would be using actual closes to do your real trading you should be using this to also do your backtesting. Rather than using adjusted data to get an idea of your total return from your backtesting, you can always add the value of the dividends and other corporate actions to the results from using the actual data. You may even find a way to add any dividends and other corporate action to your results automatically, i.e. any dividend amount added to your total return if the stock is held during the ex-dividend date. If you are using adjusted data in your backtesting this may affect any stops you have placed, i.e. it may cause your stop to be triggered earlier or later than in real trading. So you will need to determine how you will treat your stops in real trading.  Will you adjust them when there is corporate action such as dividends?  Or will you leave them constant until actual prices have gone up? If you will be leaving your stops constant then you should definitely be using actual data in your backtesting to better match your real trading. SECTION | CONTENT :--|:-- Title | Residents Devastated After Dunkin’ Donuts Closed by Fire Description | Fire Shuts Down Shamokin Dunkin Donuts Length | 0:02:25           ****   ^(I am a bot, this is an auto-generated reply | )^[Info](https://www.reddit.com/u/video_descriptionbot) ^| ^[Feedback](https://www.reddit.com/message/compose/?to=video_descriptionbot&amp;subject=Feedback) ^| ^(Reply STOP to opt out permanently) There are several reasons it is not recommended to trade stocks pre- or post-market, meaning outside of RTH (regular trading hours). Since your question is not very detailed I have to assume you trade with a time horizon of at least more than a day, meaning you do not trade intra-day. If this is true, all of the above points are a non-issue for you and a different set of points becomes important. As a general rule, using (3) is the safest regardless of what and how you trade because you get price guarantee in trade for execution guarantee. In the case of mid to longer term trading (1 week+) any of those points is viable, depending on how you want to do things, what your style is and what is the most comfortable for you. A few remarks though: (2) are market orders, so if the open is quite the ride and you are in the back of the execution queue, you can get significant slippage. (1) may require (live) data of the post-market session, which is often not easy to come by for the entire US stock universe. Depending on your physical execution method (phone, fax, online), you may lack accurate information of the post-market. If you want to execute orders based on RTH and only want to do that after hours because of personal schedule constraints, this is not really important. Personally I would always recommend (3), independent of the use case because it allows you more control over your orders and their fills. TL;DR: If you are trading long-term it does not really matter. If you go down to the intra-day level of holding time, it becomes relevant. It's a covered call.  When I want to create a covered call position, I don't need to wait before the stock transaction settles. I enter it as one trade, and they settle at different times. On most exchanges, if you place a limit order to sell at 94.64, you will be executed before the market can trade at a higher price. However most stocks in the US trade across several exchanges and your broker won't place your limit order on all exchanges (otherwise you could be executed several times). The likeliest reason for wht happened to you is that your order was not on the market where those transactions were executed. Reviewing the ticks, there were only 8 transactions above your limit, all at 1:28:24, for a total 1,864 shares and all on the NYSE ARCA exchange. If your order was on a different exchange (NYSE for example) you would not have been executed. If your broker uses a smart routing system they would not have had time to route your order to ARCA in time for execution because the market traded lower straight after. Volume at each price on that day: "EDIT: It was System Disruption or Malfunctions August 24, 2015 2:12 PM EDT   Pursuant to Rule 11890(b) NASDAQ, on its own motion, in conjunction   with BATS, and FINRA has determined to cancel all trades in security   Blackrock Capital Investment. (Nasdaq: BKCC) at or below $5.86 that   were executed in NASDAQ between 09:38:00 and 09:46:00 ET. This   decision cannot be appealed. NASDAQ will be canceling trades on the   participants behalf. A person on Reddit claimed that he was the buyer. He used Robinhood, a $0 commission broker and start-up.  The canceled trades are reflected on CTA/UTP and the current charts will differ from the one posted below.  It is an undesired effect of the 5-minute Trading Halt.  It is not ""within 1 hour of opening, BKCC traded between $0.97 and $9.5"".  Those trades only occurred for a few seconds on two occasions.  One possible reason is that when the trading halt ended, there was a lot of Market Order to sell accumulated.  Refer to the following chart, where each candle represents a 10 second period. As you can see, the low prices did not ""sustain"" for hours.   And the published halts."