Margin when entered into a derivative contract
"A derivative contract can be an option, and you can take a short (sell) position , much the same way you would in a stock. When BUYING options you risk only the money you put in. However when selling naked(you don't have the securities or cash to cover all potential losses) options, you are borrowing. Brokers force you to maintain a required amount of cash called, a maintenance requirement. When selling naked calls - theoretically you are able to lose an INFINITE amount of money, so in order to sell this type of options you have to maintain a certain level of cash in your account. If you fail to maintain this level you will enter into whats often referred to as a ""margin-call"". And yes they will call your phone and tell you :). Your broker has the right to liquidate your positions in order to meet requirements. PS: From experience my broker has never liquidated any of my holdings, but then again I've never been in a margin call for longer then a few days and never with a severe amount. The margin requirement for investors is regulated and brokers follow these regulations." The most obvious use of a collateral is as a risk buffer. Just as when you borrow money to buy a house and the bank uses the house as a collateral, so when people borrow money to loan financial instruments (or as is more accurate, gain leverage) the lender keeps a percentage of that (or an equivalent instrument) as a collateral. In the event that the borrower falls short of margin requirements, brokers (in most cases) have the right to sell that collateral and mitigate the risk.  Derivatives contracts, like any other financial instrument, come with their risks. And depending on their nature they may sometimes be much more riskier than their underlying instruments. For example, while a common stock's main risk comes from the movements in its price (which may itself result from many other macro/micro-economic factors), an option in that common stock faces risks from those factors plus the volatility of the stock's price.  To cover this risk, lenders apply much higher haircuts when lending against these derivatives. In many cases, depending upon the notional exposure of the derivative, that actual dollar amount of the collateral may be more than the face value or the market value of the derivatives contract. Usually, this collateral is deposited not as the derivatives contract itself but rather as the underlying financial instrument (an equity in case of an option, a bond in case of a CDS, and so on). This allows the lender to offset the risk by executing a trade on that collateral itself. "Derivatives derive their value from underlying assets.  This is expressed by the obligation of at least one counterparty to trade with the other counterparty in the future.  These can take on as many combinations as one can dream up as it is a matter of contract. For futures, where two parties are obligated to trade at a specific price at a specific date in the future (one buyer, one seller), if you ""short"" a future, you have entered into a contract to sell the underlying at the time specified.  If the price of the future moves against you (goes up), you will have to sell at a loss.  The bigger the move, the greater the loss.  You go ahead and pay this as well as a little extra to be sure that you satisfy what you owe due to the future.  This satisfaction is called margin. If there weren't margin, people could take huge losses on their derivative bets, not pay, and disrupt the markets.  Making sure that the money that will trade is already there makes the markets run smoothly. It's the same for shorting stocks where you borrow the stock, sell it, and wait.  You have to leave the money with the broker as well as deposit a little extra to be sure you can make good if the market moves to a large degree against you."
Futures contracts are a member of a larger class of financial assets called derivatives. Derivatives are called such because their payoffs depend on the price of other assets (financial or real). Other kinds of derivatives are call options, put options. Fixed income assets that mimic the behavior of derivatives are callable bonds, puttable bonds etc.  A futures contract is a contract that specifies the following: Just like with any other contract, there are two parties involved. One party commits to delivering the underlying asset to the other party on expiration date in exchange for the futures price. The other party commits to paying the futures price in exchange for the asset. There is no price that any of the two parties pay upfront to engage in the contract. The language used is so that the agent committing to receiving the delivery of the underlying asset is said to have bought the contract. The agent that commits to make the delivery is said to have sold the contract.  So answer your question, buying on June 1 a futures contract at the futures price of $100, with a maturity date on August 1 means you commit to paying $100 for the underlying asset on August 1. You don't have to pay anything upfront. Futures price is simply what the contract prescribes the underlying asset will exchange hands for. "Institutions and market makers tend to try and stay delta neutral, meaning that for every options contract they buy or write, they buy or sell the equivalent underlying asset. This, as a theory, is called max pain, which is more of an observation of this behavior by retail investors. This as a reality is called delta hedging done by market makers and institutional investors. The phenomenom is that many times a stock gets pinned to a very even number at a particular price on options expiration days (like 500.01 or 499.99 by closing bell). At options expiration dates, many options contracts are being closed (instutitions and market makers are typically on the other side of those trades, to keep liquidity), so for every one standard 100 share contract the market maker wrote, they bought 100 shares of the underlying asset, to remain delta neutral. When the contract closes (or get rid of the option) they sell that 100 shares of the underlying asset. At mass volume of options traded, this would cause noticeable downward pressure, similarly for other trades it would cause upward pressure as institutions close their short positions against options they had bought. The result is a pinned stock right above or below an expiration that previously had a lot of open interest. This tends to happen in more liquid stocks, than less liquid ones, to answer that question. As they have more options series and more strike prices. No, this would not be illegal, in the US attempting to ""mark the close"" is supposedly prohibited but this wouldn't count as it, the effect of derivatives on stock prices is far beyond the SEC's current enforcement regime :) although an active area of research" The basic idea behind a derivative is very simple actually.  It is a contract where the final value depends on (is derived from) the value of something else.  Stock, for instance, is not a derivative because the contract itself is actually ownership of part of a company.  Whereas car insurance is a derivative because the payout depends on the value of something else namely your (and other peoples') cars. The problem with such a simple definition is that it covers such a broad class.  It covers simple contracts like Futures where the end value just depends on the price of something on a future date.  But it extends to contracts complicated enough that people in finance call them Exotics. Derivatives are broadly used for two things reducing risk (sometimes called insurance) and speculation.  A farmer can use derivatives to make sure she gets paid a certain amount for her corn.  A banker can group a bunch of loans together and sell slices to reduce the pain of a particular loan failing.  At the same time people can use the same instruments to speculate on the price of (for example) that corn or those loans and the main advantage is that they don't have to buy the corn or loans directly.  Any farmer will tell you corn can be very expensive to store. Derivatives generally cause problems both individually and sometimes world wide when people don't properly understand the risks involved.  The most famous example being Mortgage-backed Securities and the recent Great Recession.  You can start understand the instruments and their risks by this wonderful Wikipedia article and later perhaps a used collection of CFA books which cover derivatives in great detail. Edit: Michael Grünewald mentioned Hull's text on derivatives a wonderful middle ground between Wikipedia and the CFA books that I can't believe I didn't think about myself. "This probably won't be a popular answer due to the many number of disadvantaged market participants out there but: Yes, it is possible to distort the markets for securities this way. But it is more useful to understand how this works for any market (since it is illegal in securities markets where company shares are involves).  Since you asked about the company Apple, you should be aware this is a form of market manipulation and is illegal... when dealing with securities. In any supply and demand market this is possible especially during periods when other market participants are not prevalent. Now the way to do this usually involves having multiple accounts you control, where you are acting as multiple market participants with different brokers etc. The most crafty ways to do with involve shell companies w/ brokerage accounts but this is usually to mask illegal behavior In the securities markets where there are consequences for manipulating the shares of securities. In other markets this is not necessary because there is no authority prohibiting this kind of trading behavior. Account B buys from Account A, account A buys from Account B, etc. The biggest issue is getting all of the accounts capitalized initially. The third issue is then actually being able to make a profit from doing this at all. Because eventually one of your accounts will have all of the shares or whatever, and there would still be no way to sell them because there are no other market participants to sell to, since you were the only one moving the price. Therefore this kind of market manipulation is coupled with ""promotions"" to attract liquidity to a financial product. (NOTE the mere fact of a promotion does not mean that illegal trading behavior is occurring, but it does usually mean that someone else is selling into the liquidity) Another way to make this kind of trading behavior profitable is via the derivatives market. Options contracts are priced solely by the trading price of the underlying asset, so even if your multiple account trading could only at best break even when you sell your final holdings (basically resetting the price to where it was because you started distorting it), this is fine because your real trade is in the options market. Lets say Apple was trading at $200 , the options contract at the $200 strike is a call trading at $1 with no intrinsic value. You can buy to open several thousand of the $200 strike without distorting the shares market at all,  then in the shares market you bid up Apple to $210, now your options contract is trading at $11 with $10 of intrinsic value, so you just made 1000% gain and are able to sell to close those call options. Then you unwind the rest of your trade and sell your $210 apple shares, probably for $200 or $198 or less (because there are few market participants that actually valued the shares for that high, the real bidders are at $200 and lower). This is hardly a discreet thing to do, so like I mentioned before, this is illegal in markets where actual company shares are involved and should not be attempted in stock markets but other markets won't have the same prohibitions, this is a general inefficiency in capital markets in general and certain derivatives pricing formulas. It is important to understand these things if you plan to participate in markets that claim to be fair. There is nothing novel about this sort of thing, and it is just a problem of allocating enough capital to do so." I'm not in the industry, but the point of the quoted section suggests that hybrid debt (instruments with both debt and equity features) count as acceptable capital against upcoming required capital positions.   These instruments are going to be cheaper than using common equity, and provide a leverage effect that can improve the return on equity (same income/cash flow over lower required equity). "Is there ever any ambiguity on what that that exact strike is in delta space, or does everyone back it out from the pricing model the same way?  I ask, because in my product nearly everyone runs a heavier delta to the put (the severity of that varies). So on trades that are ""tied up"", everyone participating on it can have slightly different deltas that they are modeling" "You gave your own answer - the 80% is positions, not contracts. Most actors on the option market have no interest in the underlying asset. They want ""just"" exposure to its price movement. It makes more sense to close your position than to be handed over bushels of wheat or whatever." You have to call Interactive Brokers for this. This is what you should do, they might even have a web chat. These are very broker specific idiosyncrasies, because although margin rules are standardized to an extent, when they start charging you for interest and giving you margin until settlement may not be standardized. I mean, I can call them and tell you what they said for the 100 rep.