Setting a trailing stop loss at $39.70 bid price, stock sold at $41
There could be a number of reasons: The price hit your number ($39.70) but by the time your order hit the market, the price had gone up. Perhaps the stock went up between when you placed the stop loss and when the order was executed. A trailing stop loss will ratchet up: Very simply, the trailing stop maintains a stop-loss order at a precise percentage below the market price (or above, in the case of a short position). The stop-loss order is adjusted continually based on fluctuations in the market price, always maintaining the same percentage below (or above) the market price. Is this due to the delay?  Yes, but the delay is caused by your broker and its affiliates.  Trailing Stop Order is not exchange native, meaning that the broker is responsible for keeping track of whether the stop price has been reached, and the broker is responsible for sending the subsequent Market Order to the exchange.  For certain exchange, even Stop Order or Stop Limit Order is not exchange native.  Is it common to be so different? No, only in times of extreme volatility.
"I would normally take a cautious, ""it depends"" approach to answering a question like this, but instead I'm going to give you a blunt opinionated answer based solely on what I would do: Even the crap. Get rid of them and get into the boring low fee mutual funds.  I was in a similar situation a few years ago, almost. My retirement accounts were already in funds but my brokerage account was all individual stocks.  I decided I didn't really know what I was doing despite being up by 30+% (I recognize that it was mostly due to the market itself being up, I was lucky basically). The way I cashed out was not to sell all at once. I just set up trailing stops on all of them and waited until they hit the stops. The basic idea was that if the market kept going up, the point at which they got sold also went up (it was like a 10% trail I think), and once things started to turn for that stock, they would sell automatically.  Sure I sold some at very temporary dips so I missed out on some gains but that's always a risk with a trailing stop and I really didn't care at that point.  If I had to do it again, I might forget all that and just sell all at once.  But I feel a lot better not being in individual stocks." "Both explanations are partly true. There are many investors who do not want to sell an asset at a loss.  This causes ""resistance"" at prices where large amounts of the asset were previously traded by such investors.  It also explains why a ""break-through"" of such a ""resistance"" is often associated with a substantial ""move"" in price. There are also many investors who have ""stop-loss"" or ""trailing stop-loss"" ""limit orders"" in effect.  These investors will automatically sell out of a long position (or buy out of a short position) if the price drops (or rises) by a certain percentage (typically 8% - 10%). There are periods of time when money is flowing into an asset or asset class.  This could be due to a large investor trying to quietly purchase the asset in a way that avoids raising the price earlier than necessary.  Or perhaps a large investor is dollar-cost-averaging.  Or perhaps a legal mandate for a category of investors has changed, and they need to rebalance their portfolios.  This rebalancing is likely to take place over time.  Or perhaps there is a fad where many small investors (at various times) decide to increase (or decrease) their stake in an asset class.  Or perhaps (for demographic reasons) the number of investors in a particular situation is increasing, so there are more investors who want to make particular investments.  All of these phenomena can be summarized by the word ""momentum"". Traders who use technical analysis (including most day traders and algorithmic speculators) are aware of these phenomena.  They are therefore more likely to purchase (or sell, or short) an asset shortly after one of their ""buy signals"" or ""sell signals"" is triggered.  This reinforces the phenomena. There are also poorly-understood long-term cycles that affect business fundamentals and/or the politics that constrain business activity.  For example: Note that even if the markets really were a random walk, it would still be profitable (and risk-reducing) to perform dollar-cost-averaging when buying into a position, and also perform averaging when selling out of a position.  But this means that recent investor behavior can be used to predict the near-future behavior of investors, which justifies technical analysis." The price of a share has two components: Bid: The highest price that someone who wants to buy shares is willing to pay for them. Ask: The lowest price that someone who has a share is willing to sell it for. The ask is always higher than the bid, since if they were equal the buyer and seller would have a deal, make a transaction, and that repeats until they are not equal. For stock with high volume, there is usually a very small difference between the bid and ask, but a stock with lower volume could have a major difference. When you say that the share price is $100, that could mean different things. You could be talking about the price that the shares sold for in the most recent transaction (and that might not even be between the current bid and ask), or you could be talking about any of the bid, the ask, or some value in between them. If you have shares that you are interested in selling, then the bid is what you could immediately sell a share for. If you sell a share for $100, that means someone was willing to pay you $100 for it. If after buying it, they still want to buy more for $100 each, or someone else does, then the bid is still $100, and you haven't changed the price. If no one else is willing to pay more than $90 for a share, then the price would drop to $90 next time a transaction takes place and thats what you would be able to immediately sell the next share for. "An important thing that many people fail to realize is that the number of shares outstanding in a stock, times the current market price of those shares, does not represent anything related to the total value of those shares.  If a company has one million shares outstanding and its total value is $10 million, then the real worth of each share is $10.  If few people feels like buying or selling, but a few people think the company is worth $50 million and offer $50/share, that could raise the market price to $50/share, but it wouldn't mean that the company became worth five times as much; it would merely mean the stock was overpriced. If, after the price went to $50/share, all the owners of the stock put in stop-loss orders at $45.  Note that the real $10/share ""real value"" of their stock would never have changed.  If the people who thought the stock was worth $50 decided to get out of the market, and nobody else was willing to offer more than $10, that would instantly drop the price to $10.  The fact that a million shares of stock have stop-loss orders at $45 wouldn't magically generate buyers for those stocks at that price.  Indeed, unchecked stop-loss orders would have the reverse effect, since many people who would have been willing if not eager to buy the stock if it had been available for less than $10/share would instead be trying to sell it below that price. It's too bad people think that the number of shares outstanding times the current market price represents some kind of ""meaningful quantity"".  If the present cash value of all future payouts associated with a share of stock is $10, then someone who buys a share of stock for less than that makes money off the seller; someone who pays more loses money to the seller.  Many people think they can lose money to the seller and still come out okay if the price goes higher, but what that really means is that they're hoping to find a bigger sucker--a game where it's guaranteed that some people will have losses they don't recoup." William %R is a momentum indicator used for measuring overbought and oversold levels, it is not used to predict the price of a stock. In fact, William %R, like all momentum indicators, is a lagging indicator - meaning the indicator level changes as the price of the stock changes. It ranges from 0 to -100. Usually when a reading is less than -80 the stock can be considered to be oversold, and when the reading is above -20 the stock can be considered overbought. When viewed together with the price chart, this can help provide a trader with entry and exit points into and out of a trade. I'm not entirely sure about some of the details in your question, since I think you meant to use $10,000 as the value of the futures contract and $3 as the value of the underlying stock. Those numbers would make more sense. That being said, I can give you a simple example of how to calculate the profit and loss from a leveraged futures contract. For the sake of simplicity, I'll use a well-known futures contract: the E-mini S&P500 contract. Each E-mini is worth $50 times the value of the S&P 500 index and has a tick size of 0.25, so the minimum price change is 0.25 * $50 = $12.50.  Here's an example. Say the current value of the S&P500 is 1,600; the value of each contract is therefore $50 * 1,600 = $80,000. You purchase one contract on margin, with an initial margin requirement1 of 5%, or $4,000. If the S&P 500 index rises to 1,610, the value of your futures contract increases to $50 * 1,610 = $80,500. Once you return the 80,000 - 4,000 = $76,000 that you borrowed as leverage, your profit is 80,500 - 76,000 = $4,500.  Since you used $4,000 of your own funds as an initial margin, your profit, excluding commissions is 4,500 - 4,000 = $500, which is a 500/4000 = 12.5% return. If the index dropped to 1,580, the value of your futures contract decreases to $50 * 1,580 = $79,000. After you return the $76,000 in leverage, you're left with $3,000, or a net loss of (3,000 - 4000)/(4000) = -25%. The math illustrates why using leverage increases your risk, but also increases your potential for return. Consider the first scenario, in which the index increases to 1,610. If you had forgone using margin and spent $80,000 of your own funds, your profit would be (80,500 - 80,000) / 80000 = .625%. This is smaller than your leveraged profit by a factor of 20, the inverse of the margin requirement (.625% / .05 = 12.5%). In this case, the use of leverage dramatically increased your rate of return.  However, in the case of a decrease, you spent $80,000, but gained $79,000, for a loss of only 1.25%. This is 20 times smaller in magnitude than your negative return when using leverage. By forgoing leverage, you've decreased your opportunity for upside, but also decreased your downside risk. 1) For futures contracts, the margin requirements are set by the exchange, which is CME group, in the case of the E-mini. The 5% in my example is higher than the actual margin requirement, which is currently $3,850 USD per contract, but it keeps the numbers simple. Also note that CME group refers to the initial margin as the performance bond instead. It will depend largely on your broker what type of stop and trailing stop orders they provide. Saying that, I have not come across any brokers yet that offer limit orders with trailing stop orders.  Unlike a standard stop order where you can either make it a market stop order or a limit stop order, usually most brokers have trailing stop orders as market orders only, where you can either set the trailing stop to be a dollar value or percentage from the most recent high. Remember also, that trailing stop orders will be based on the intra-day highs and not the highest closing price. That means that if the share price spikes up during the day your trailing stop will move up, and if the price then spikes down you may be stopped out prematurely, after which the price might rally again. For this reason I try to base my trailing stops on the highest closing price by using standard stop loss orders and moving it up manually after the close of trade if the share price has closed at a new high. This takes a few minutes each evening (depending on how many stocks you have to check and adjust the stops for) but gives you more control. Using this method will also enable you to set limit orders attached to your stop loss triggers, and you won't have to keep your trailing too close to the last high price thus potentially causing you to get stopped out prematurely. Slightly off track but may be handy if you set profit targets, my broker has recently introduced Trailing Take Profit Orders. The way it works is, say you have a profit target of 50%, so you buy at $2 and want to take profits if the price reaches $3, you could set your Trailing Take Profit Trigger at say $3.10 or above and set a Trail by Amount of say $0.10. So if the price after hitting $3.10 falls to $3.00 you will be stopped out and collect your profits. If the price moves up to $3.30 and then falls to $3.20, you will be stopped out at $3.20 and make some extra profits. If the price continues going up the Trailing Take Profit will continue to move up always $0.10 below the highest price reached. I think this would be a very useful order if you were range trading where you could set the Trailing Take Profit trigger near recent resistance so you can get out if prices start reversing at or around the resistance, but continue profiting if the price breaks through the resistance. Price for the latest transaction. If the stock is selling for  $898.7 means that the stock is currently trading for  $898.7, and it will be your ask price of stock if you purchase currently.