Purchasing options between the bid and ask prices, or even at the bid price or below?
I understand the question, I think. The tough thing is that trades over the next brief time are random, or appear so. So, just as when a stock is $10.00 bid / $10.05 ask, if you place an order below the ask, a tick down in price may get you a fill, or if the next trades are flat to higher, you might see the close at $10.50, and no fill as it never went down to your limit.  This process is no different for options than for stocks.  When I want to trade options, I make sure the strike has decent volume, and enter a market order. Edit - I reworded a bit to clarify. The Black–Scholes is a model, not a rigid equation. Say I discover an option that's underpriced, but it trades under right until it expires. It's not like there's a reversion to the mean that will occur. There are some very sophisticated traders who use these tools to trade in some very high volumes, for them, it may produce results. For the small trader you need to know why you want to buy a stock or its option and not worry about the last $0.25 of its price. "Yes, almost always. I trade some of the most illiquid single stock options, and I would be absolutely murdered if I didn't try to work orders between the bid/ask.  When I say illiquid, I mean almost non-existent: ~50 monthly contracts on ALL contracts for a given underlying.  Spreads of 30% or more. The only time you shouldn't try to work an order, in my opinion, is when you think you need to trade immediately (rare), if implied volatility (IV) has moved to such a degree that the market makers (MM) won't hit your order while they're offering fair IV (they'll sometimes come down to meet you at their ""real"" price to get the exchange's liquidity rebate), or if the bid/ask spread is a penny. For illiquid single stock options, you need to be extremely mindful of implied and statistical volatility.  You can't just try to always put your order in the middle.  The MMs will play with the middle to get you to buy at higher IVs and sell at lower. The only way you can hope that an order working below the bid / above the ask will get filled is if a big player overwhelms the MMs' (who are lined up on the bid and ask) current orders and hits yours with one large order.  I've never seen this happen. The only other way is like you said: if the market moves against you, the orders in front of yours disappear, and someone hits your order, but I think that defeats the intent of your question." "People must simply be willing to match your orders if they know about it. You can sniff orders out if you can see them or predict them. For instance, you can look at an order book and decide who you want to get filled at, especially if you are looking at different quotes from different exchanges. So you can get a ""better"" fill just by looking at what someone is willing to pay to enter/exit their order as well as what exchange they placed their order through, and send an order to that specific exchange to match them. You (or a program) can just watch the level 2's and place an order as soon as you see one you like. The orders on the level2's do not reveal ALL interested market participants. Also many brokers have difficulty updating options quotes. Finally, options & market volatility can inflate or decrease the price of options by large percentages very quickly." I frequently do this on NADEX, selling out-of-the-money binary  calls. NADEX is highly illiquid, and the bid/ask is almost always from  the market maker. Out-of-the-money binary calls lose value quickly  (NADEX daily options exist for only ~21 hours). If I place an  above-ask order, it either gets filled quickly (within a few minutes)  due to a spike in the underlying, or not at all. I compensate by  changing my price hourly.  As Joe notes, one of Black-Scholes inputs is volatility, but price  determines (implied) volatility, so this is circular. In other words, you can  treat the bid/ask prices as bid/ask volatilities. This isn't as  far-fetched as it seems:  http://www.cmegroup.com/trading/fx/volatility-quoting-fx-options.html This sometimes happens to me. It depends on how liquid the option is. Normally what I see happening is that the order book mutates itself around my order. I interpret this to mean that the order book is primarily market makers. They see a retail investor (me) come in and, since they don't have any interest in this illiquid option, they back off. Some other retail investor (or whatever) steps in with a market order, and we get matched up. I get a fill because I become the market maker for a brief while. On highly liquid options, buy limits at the bid tend to get swallowed because the market makers are working the spread. With very small orders (a contract or two) on very liquid options, I've had luck getting quick fills in the middle of the spread, which I attribute to MM's rebalancing their holdings on the cheap, although sometimes I like to think there's some other anal-retentive like me out there that hates to see such a lopsided book. :) I haven't noticed any particular tendency for this to happen more with puts or calls, or with buy vs sell transactions. For a while I had a suspicion that this was happening with strikes where IV didn't match IV of other strikes, but I never cared enough to chase it down as it was a minor part of my overall P/L.
You said the decision will be made by EOD. If you've made the decision prior to the market close, I'd execute on the closing price.  If you are trading stocks with any decent volume, I'd not worry about the liquidity.  If your strategy's profits are so small that your gains are significantly impacted by say, the bid/ask spread (a penny or less for liquid stocks) I'd rethink the approach. You'll find the difference between the market open and prior night close is far greater than the normal bid/ask. It could be that the contracts were bought at cheaper prices such as $.01 earlier in the day. What you see there with the bid and ask is the CURRENT bid and CURRENT ask. The high ask price means there is no current liquidity, as someone is quoting a very high ask price just in case someone really wants to trade that price. But as you said, no one would buy this with a better price on a closer strike price. The volume likely occurred at a different price than listed on the current ask. "In a sense, yes. There's a view in Yahoo Finance that looks like this   For this particular stock, a market order for 3000 shares (not even $4000, this is a reasonably small figure) will move the stock past $1.34, more than a 3% move.  Say, on the Ask side there are 100,000 shares, all with $10 ask. It would take a lot of orders to purchase all these shares, so for a while, the price may stay right at $10, or a bit lower if there are those willing to sell lower.  But, say that side showed $10 1000, $10.25 500, $10.50 1000. Now, the volume is so low that if I decided I wanted shares at any price, my order, a market order will actually drive the market price right up to $10.50 if I buy 2500 shares ""market"".  You see, however, even though I'm a small trader, I drove the price up. But now that the price is $10.50 when I go to sell all 2500 at $10.50, there are no bids to pay that much, so the price the next trade will occur at isn't known yet. There may be bids at $10, with asking (me) at $10.50. No trades will happen until a seller takes the $10 bid or other buyers and sellers come in." "I'm not sure the term actually has a clear meaning. We can think of ""what does this mean"" in two ways: its broad semantic/metaphorical meaning, and its mechanical ""what actual variables in the market represent this quantity"". Net buying/selling have a clear meaning in the former sense by analogy to the basic concept of supply and demand in equilibrium markets. It's not as clear what their meaning should be in the latter sense. Roughly, as the top comment notes, you could say that a price decrease is because of net selling at the previous price level, while a price rise is driven by net buying at the previous price level. But in terms of actual market mechanics, the only way prices move is by matching of a buyer and a seller, so every market transaction inherently represents an instantaneous balance across the bid/ask spread. So then we could think about the notion of orders. Actual transactions only occur in balance, but there is a whole book of standing orders at various prices. So maybe we could use some measure of the volume at various price levels in each of the bid/ask books to decide some notion of net buying/selling. But again, actual transactions occur only when matched across the spread. If a significant order volume is added on one side or the other, but at a price far away from the bid/offer - far enough that an actual trade at that price is unlikely to occur - should that be included in the notion of net buying/selling? Presumably there is some price distance from the bid/offer where the orders don't matter for net buying/selling. I'm sure you'd find a lot of buyers for BRK.A at $1, but that's completely irrelevant to the notion of net buying/selling in BRK.A. Maybe the closest thing I can think of in terms of actual market mechanics is the comparative total volumes during the period that would still have been executed if forced to execute at the end of period price. Assuming that traders' valuations are fixed through the period in question, and trading occurs on the basis of fundamentals (which I know isn't a good assumption in practice, but the impact of price history upon future price is too complex for this analysis), we have two cases. If price falls, we can assume all buyers who executed above the last price in the period would have happily bought at the last price (saving money), while all sellers who executed below the last price in the period would also be happy to sell for more. The former will be larger than the latter. If the price rises, the reverse is true." The time when you might want to do this is if you think BBY is undervalued already.  If you'd be happy buying the stock now, you'd be happy buying it lower (at the strike price of the put option you sold).  If the stock doesn't go down, you win.  If it does, you still win, because you get the stock at the strike price. If I recall correctly Warren Buffett did this with Coca-Cola.  But that's Warren Buffett. Options are a derivative product, and in this case, derive their value from an underlying security, a traded stock. An option gives you the right, but not the obligation, to buy a stock at a given price (the strike price) by a given time (the expiration date.) What I just described is a call option. The opposite instrument is a put, giving you the right, but not the obligation, to sell the stock at a given price.  Volumes have been written on the subject, but I'd suggest that for a custodial Roth, I'd not activate the ability to trade options.  How to get started with options investing? offers a nice introduction to trading options. In my response, I offer an example of a trade that's actually less risky due to the option component. "EVERYONE buys at the ask price and sells at the bid price (no matter who you are). There are a few important things you need to understand. Example: EVE bid: 16.00 EVE ask: 16.25 So if your selling EVE at ""market price"" you are entering an ask equal to the highest bid ($16.00). If you buy EVE at ""market price"" you are entering a bid equal to the lowest ask price ($16.25). Its key to understand this rule: ""An order executes ONLY when both bid and ask meet. (bid = ask)."" So a market maker puts in a bid when he wants to buy but the trade only executes when an ASK price meets his BID price. When you see a quote for a stock it is the price of the last trade. So it is possible to have a quote higher or lower then both the bid and the ask." Volume @ 0 doesn't mean that there are no buyers and sellers, it just means that there hasn't been any trades done yet. What you need to look for are the bids and offers (for selling and buying, respectively). For further expiration and NTM or IT options there will almost always be a bid and an offer (but it may be very wide). Now, in case where there is 0 bid (no one is willing to buy), you may still have a chance if the option has some value in it. For that - you need your broker to try to shop it to market making firms. Now, depending on who your broker is, this may or may not be possible. Alternatively, if you have DMA (direct market access) to the options exchanges, you can try to put in an offer of your own and wait for someone to execute against you, however do not expect to be traded with unless your price is out of line with the cost. However, in wide markets, you can try Lampost options (they may give you price improvement) or try to offer very close to the bid. You may save yourself a penny or two and perhaps get a rebate if you are using BATSO or NASDAQO markets (if you have DMA and pass-through exchange fees).