how derivatives transfer risk from one entity to another
By buying the call option, you are getting the benefit of purchasing the underlying shares (that is, if the shares go up in value, you make money), but transferring the risk of the shares reducing in value. This is more apparent when you are using the option to offset an explicit risk that you hold. For example, if you have a short position, you are at unlimited risk of the position going up in value. You could decide you only want to take the risk that it might rise to $X. In that case, you could buy a call option with $X strike price. Then you have transferred the risk that the position goes over $X to the counterpart, since, even if the shares are trading at $X+$Y you can close out the short position by purchasing the shares at $X, while the option counterpart will lose $Y. When you buy a call option, you transfer the risk to the owner of the asset. They are risking losing out on gains that may accumulate in addition to the strike price and paid premium. For example, if you buy a $25 call option on stock XYZ for $1 per contract, then any additional gain above $26 per share of XYZ is missed out on by the owner of the stock and solely benefits the option holder. The important thing to realize is, what would you do, if you didn't have the call? If you didn't have call options, but you wanted to have a position in that particular stock, you would have to actually purchase it. But, having purchased the shares, you are at risk to lose up to the entire value of them-- if the company folded or something like that.  A call option reduces the potential loss, since you are at worst only out the cost of the call, and you also lose a little on the upside, since you had to pay for the call, which will certainly have some premium over buying the underlying share directly. Risk can be defined as reducing the variability of outcomes, so since calls/shorts etc. reduce potential losses and also slightly reduce potential gains, they pretty much by definition reduce risk. It's also worth noting, that when you buy a call, the seller could also be seen as hedging the risk of price decreases while also guaranteeing that they have a buyer at a certain price. So, they may be more concerned about having cash flow at the right time, while at the same time reducing the cost of the share losing in value than they are losing the potential upside if you do exercise the option. Shorts work in the same way but opposite direction to calls, and forwards and futures contracts are more about cash flow management: making sure you have the right amount of money in the right currency at the right time regardless of changes in the costs of raw materials or currencies. While either party may lose on the transaction due to price fluctuations, both parties stand to gain by being able to know exactly what they will get, and exactly what they will have to pay for it, so that certainty is worth something, and certainly better for some firms than leaving positions exposed. Of course you can use them for speculative purposes, and a good number of firms/people do but that's not really why they were invented.
"I struggled with this one at first.   It's easiest if you temporarily ignore the mathematical machinery of martingales and go back to the derivation that Black and Scholes provide in their 1973 paper. They basically show that when you construct a portfolio consisting of a long position in the option (the one being priced) and a short position on the replicating portfolio (consisting of shares of stock and cash in the risk-free bank account), then that portfolio will be entirely risk-less, and hence will earn the risk-free rate of interest. This makes intuitive sense if you think about it - every change in the value of the option is going to be countered by an opposite change in the replicating portfolio; by no arbitrage, that composite portfolio (the option + the replicating portfolio) must therefore earn the risk-free rate.   The fact that the composite portfolio earns the risk-free rate provides the connection to martingale pricing.   Recall that a martingale is basically* a stochastic process that has no drift, only volatility. Here, it's useful to think of the drift as being the ""risk  premium"" or ""return"" of a particular asset (like the stock).   What martingale pricing theory says is that to find the price of the option we (1) discount the value of the replicating portfolio by the cash bond (the numeraire asset), and (2) turn the stochastic process of the risky asset in the replicating portfolio into a martingale. This move intuitively makes sense because the Black-Scholes derivation shows that the replicating portfolio + the option must earn the risk-free rate, but if you divide the value of the Black-Scholes replicating portfolio by the numeraire asset, you're going to cancel out that risk-free rate -- e.g. have a Martingale.  (I'm not a mathematician, so please correct me if I've mucked something up in my explanation).   *I say basically because there are some technical conditions that need to be fulfilled, but that's generally true." I used to trade power for a closed end hedge fund.   Yes, weather derivatives are very important.  They help power traders / utilities hedge for unaccountable variables, IE weather.  For example, lets say it costs a utility $50 an hour to produce power for the load when it is 80 degrees outside.  Lets say I trade the contract with them to guarantee the weather will be under 80 degrees.  If the weather is higher than 80 degrees, more people turn in their AC, the load on the grid goes up, and the utility has to start generating power at $70 an hour.    Under this contract, I would be liable to pay the utility the net difference in their cost (the additional $20 per hour they generate per mw).  In that case I am a loser.  If the power comes in under 80 degrees, I make money as I priced (sold) the contract at a premium according to the risk I calulated for offereing the contract.  This has many many applications, but yes, its not a weird thing to trade.  Hope this helps. It's not! With gambling, you're placing a bet on some team's performance but you don't own the team, or the field they play on, or the other team, or the ball!  Derivatives are just like that! Except with derivatives, the team can bet against themselves, and not tell you that they have! As far as I can see, it misses the most important point (from the perspective of a private person), for most derivatives: It's marketing.  There are a bunch of derivatives out there which are ONLY traded by (and actively marketed to) retail investors, no instutional investors or companies. They are complex and, in terms of the combination of risk and reward, inferior to plain-vanilla classic derivatives, which gives the bank a better margin... "As Dheer pointed out, Wikipedia has a good definition of what a negotiable instrument is.  A security is an instrument or certificate that signifies an ownership interest in something tangible. 1 share of IBM represents some small fraction of a company. You always have the ability to choose a price you are willing to pay -- which may or may not be the price that you get. A derivative is a level of abstraction linked by a contract to a security... if you purchase a ""Put"" contract on IBM stock, you have a contractural right to sell IBM shares at a specific price on a specific date. When you ""own"" a derivative, you own a contract -- not the actual security." "MD-Tech answered: The answer is in your question: derivatives are contracts so are enforced in the same way as any other contract.  If the counterparty refuses to pay immediately they will, in the first instance be billed by any intermediary (Prime Broker etc.) that facilitated the contract. If they still refuse to pay the contract may stipulate that a broker can ""net off"" any outstanding payments against it or pay out using deposited cash or posted margins. The contract will usually include the broker as an interested party and so they can, but don't need to, report a default (such that this is) to credit agencies (in some jurisdictions they are required to by law). Any parties to the trade and the courts may use a debt collection agency to collect payments or seize assets to cover payment. If there is no broker or the counterparty still has not paid the bill then the parties involved (the party to the trade and any intermediaries) can sue for breach of contract. If they win (which would be expected) the counterparty will be made to pay by the legal system including, but not limited to, seizure of assets, enforced bankruptcy, and prison terms for any contempts of court rulings. All of this holds for governments who refuse to pay derivatives losses (as Argentina did in the early 20th century) but in that case it may escalate as far as war. It has never done so for derivatives contracts as far as I know but other breaches of contract between countries have resulted in armed conflict. As well as the ""hard"" results of failing to pay there are soft implications including a guaranteed fall in credit ratings that will result in parties refusing to do business with the counterparty and a separate loss of reputation that will reduce business even further. Potential employees and funders will be unwilling to become involved with such a party and suppliers will be unwilling to supply on credit. The end result in almost every way would be bankruptcy and prison sentences for the party or their senior employees. Most jurisdictions allow for board members at companies in material breach of contract to be banned from running any company for a set period as well. edit: netting off cash flows netting off is a process whereby all of a party's cash flows, positive and negative, are used to pay each other off so that only the net change is reflected in account balances, for example: company 1 cash flows netting off the total outgoings are 3M + 500k = 3.5M and total incomings are 1.2M + 1.1M + 1.2M = 3.5M so the incoming cash flows can be used to pay the outgoing cash flows leaving a net payment into company1's account of 0." It makes sense for a lot of people - it's basically weather insurance. It's useful for farmers (bad weather ruining a harvest), airlines (abnormally high amount of snowstorms increasing cost of delayed flights), hotels (rain making people visit less), ski resorts (not enough snow) and other businesses that can be negatively impacted by extreme weather variations.  If they systematically slightly overpay for this protection the speculator can make money on net helping these businesses reduce the volatility of their cashflows which is important because they need to pay their overhead costs every year.  Edit: The derivatives themselves also allows the people selling weather insurance to hedge their exposure on the market. Generally, anyone can. Selling them is an interesting point, as the buyer has a counterparty risk that you won't be able to pay at the term of the contract. So, if I was a vendor buying a derivative in my example, I would definitely get that derivative from a bank as opposed to my friend Jim Bob. Especially in cases of bespoke derivatives, it doesn't make sense for anyone except people who have material interest to by it, as the expectation value of the hedge is negative. Essentially, you're more likely to lose money than gain money from a hedge. The exception is when you have information above that of the market, which could allow for a positive return. That is the reason that people advocate for derivatives as mechanisms of price discovery, because large imbalances aren't likely to form when someone could arbitrage or even just take positions when the market goes out of whack. That only really works in publically traded markets, however, bespoke derivatives don't really contribute to better pricing afaik.  Of course, that's the simple explanation to a huge, complex, and varied field. Certainly, speculators exist, particularly in the more commoditized derivatives. Especially in the leadup to the financial crisis, large amounts were spent on exotic derivatives that blew up in people's faces. The easiest thing to say about them is that they are double edged swords. In theory, they're fantastic, as it allows risk to be spread around to people that want it. It should lead to a safer system, as hedged comapnies are less exposed to shocks and are more resilient. But in practice, we've alao seen them used as risk concentrators (AIG). We've seen cases where correlations arise that weren't assumed before, and what used to be manageable positions become lead weights. We've seen the dangers that large systemically important financial institutions have when they are a counterparty to tens of trillions in notional derivatives, as when they fail the risk of failure is over every derivative they are counterparty to, not just the hedged exposure.   Sorry, this is more than you asked for. I tend to get carried away. "Seems like you are concerned with something called assignment risk. It's an inherent risk of selling options: you are giving somebody the right, but not the obligation, to sell to you 100 shares of GOOGL. Option buyers pay a premium to have that right - the extrinsic value. When they exercise the option, the option immediately disappears. Together with it, all the extrinsic value disappears. So, the lower the extrinsic value, the higher the assignment risk. Usually, option contracts that are very close to expiration (let's say, around 2 to 3 weeks to expiration or less) have significantly lower extrinsic value than longer option contracts. Also, generally speaking, the deeper ITM an option contract is, the lower extrinsic value it will have. So, to reduce assignment risk, I usually close out my option positions 1-2 weeks before expiration, especially the contracts that are deep in the money. edit: to make sure this is clear, based on a comment I've just seen on your question. To ""close out an options position"", you just have to create the ""opposite"" trade. So, if you sell a Put, you close that by buying back that exact same put. Just like stock: if you buy stock, you have a position; you close that position by selling the exact same stock, in the exact same amount. That's a very common thing to do with options. A post in Tradeking's forums, very old post, but with an interesting piece of data from the OCC, states that 35% of the options expire worthless, and 48% are bought or sold before expiration to close the position - only 17% of the contracts are actually exercised! (http://community.tradeking.com/members/optionsguy/blogs/11260-what-percentage-of-options-get-exercised) A few other things to keep in mind: certain stocks have ""mini options contracts"", that would correspond to a lot of 10 shares of stock. These contracts are usually not very liquid, though, so you might not get great prices when opening/closing positions you said in a comment, ""I cannot use this strategy to buy stocks like GOOGL""; if the reason is because 100*GOOGL is too much to fit in your buying power, that's a pretty big risk - the assignment could result in a margin call! if margin call is not really your concern, but your concern is more like the risk of holding 100 shares of GOOGL, you can help manage that by buying some lower strike Puts (that have smaller absolute delta than your Put), or selling some calls against your short put. Both strategies, while very different, will effectively reduce your delta exposure. You'd get 100 deltas from the 100 shares of GOOGL, but you'd get some negative deltas by holding the lower strike Put, or by writing the higher strike Call. So as the stock moves around, your account value would move less than the exposure equivalent to 100 shares of stock." First, realize that Wikipedia is written by individuals, just like this board has thousands of members. The two definition were written and edited by different people, most likely.  Think Venn diagram.  The definition for financial instruments claims that it's the larger set, and securities is contained in a subset.  Comparing the two, it seems pretty consistent.  Yes, Securities include derivatives.  Transferable is close to tradable, although to me tradable implies a market as compared to private transfers.  I don't believe there's an opposite, per se, but there's 'other stuff.' My house has value, but is not a security. My coffee cup has no value. Back to the concept of Venn. There aren't really opposites, just items falling outside the set we're discussing.  I'd caution, this is a semantic exercise. If you know what you're buying, a stock, a bond, a gold bar, etc, whether it's a financial instrument or security doesn't matter to you. I think your premise is slightly flawed. Every investment can add or reduce risk, depending on how it's used. If your ordering above is intended to represent the probability you will lose your principal, then it's roughly right, with caveats. If you buy a long-term government bond and interest rates increase while you're holding it, its value will decrease on the secondary markets. If you need/want to sell it before maturity, you may not recover your principal, and if you hold it, you will probably be subject to erosion of value due to inflation (inflation and interest rates are correlated). Over the short-term, the stock market can be very volatile, and you can suffer large paper losses. But over the long-term (decades), the stock market has beaten inflation. But this is true in aggregate, so, if you want to decrease equity risk, you need to invest in a very diversified portfolio (index mutual funds) and hold the portfolio for a long time. With a strategy like this, the stock market is not that risky over time. Derivatives, if used for their original purpose, can actually reduce volatility (and therefore risk) by reducing both the upside and downside of your other investments. For example, if you sell covered calls on your equity investments, you get an income stream as long as the underlying equities have a value that stays below the strike price. The cost to you is that you are forced to sell the equity at the strike price if its value increases above that. The person on the other side of that transaction loses the price of the call if the equity price doesn't go up, but gets a benefit if it does. In the commodity markets, Southwest Airlines used derivatives (options to buy at a fixed price in the future) on fuel to hedge against increases in fuel prices for years. This way, they added predictability to their cost structure and were able to beat the competition when fuel prices rose. Even had fuel prices dropped to zero, their exposure was limited to the pre-negotiated price of the fuel, which they'd already planned for. On the other hand, if you start doing things like selling uncovered calls, you expose yourself to potentially infinite losses, since there are no caps on how high the price of a stock can go. So it's not possible to say that derivatives as a class of investment are risky per se, because they can be used to reduce risk. I would take hedge funds, as a class, out of your list. You can't generally invest in those unless you have quite a lot of money, and they use strategies that vary widely, many of which are quite risky. "I am assuming you mean derivatives such as speeders, sprinters, turbo's or factors when you say ""derivatives"". These derivatives are rather popular in European markets. In such derivatives, a bank borrows the leverage to you, and depending on the leverage factor you may own between 50% to +-3% of the underlying value. The main catch with such derivatives from stocks as opposed to owning the stock itself are: Counterpart risk: The bank could go bankrupt in which case the derivatives will lose all their value even if the underlying stock is sound. Or the bank could decide to phase out the certificate forcing you to sell in an undesirable situation. Spread costs: The bank will sell and buy the certificate at a spread price to ensure it always makes a profit. The spread can be 1, 5, or even 10 pips, which can translate to a the bank taking up to 10% of your profits on the spread.  Price complexity: The bank buys and sells the (long) certificate at a price that is proportional to the price of the underlying value, but it usually does so in a rather complex way. If the share rises by €1, the (long) certificate will also rise, but not by €1, often not even by leverage * €1.  The factors that go into determining the price are  are normally documented in the prospectus of the certificate but that may be hard to find on the internet. Furthermore the bank often makes the calculation complex on purpose to dissimulate commissions or other kickbacks to itself in it's certificate prices.  Double Commissions: You will have to pay your broker the commission costs for buying the certificate. However, the bank that issues the derivative certificate normally makes you pay the commission costs they incur by hiding them in the price of the certificate by reducing your effective leverage. In effect you pay commissions twice, once directly for buying the derivative, and once to the bank to allow it to buy the stock.  So as Havoc P says, there is no free lunch. The bank makes you pay for the convenience of providing you the leverage in several ways. As an alternative, futures can also give you leverage, but they have different downsides such as margin requirements. However, even with all the all the drawbacks of such derivative certificates, I think that they have enough benefits to be useful for short term investments or speculation." "JoeTaxpayer's answer adequately explained leverage and some of your risks.   Your risks also include: The firm's risk is that you will figure out a way to leave them with a negative account that contributes to another customer's profit and yet you disappear in a way that makes the negative account impossible to collect. Another risk is that you are not who you say you are, or that the money you invest is not yours.  These are called ""know your customer"" risks." No. Such companies don't exist. Derivative instruments have evolved over a period and there is a market place, stock exchange with members / broker with obligations etc clearly laid out and enforceable. If I understand correctly say the house is at 300 K. You would like a option to sell it to someone for 300 K after 6 months. Lets say you are ready to pay a premium of 10K for this option. After 6 months, if the market price is 400 K you would not exercise the option and if the market price of your house is 200 K you would exercise the option and ask the option writer to buy your house for 300 K. There are quite a few challenges, i.e. who will moderate this transaction. How do we arrive that house is valued at 300K. There could be actions taken by you to damage the property and hence its reduction in value, etc. i.e. A stock exchange like market place for house is not there and it may or may not develop in future. When we 'delta-hedge', we make the value of a portfolio 0.  No - you make the risk relative to some underlying 0.  The portfolio does have a value, but if whatever underlying you're hedging against changes slightly the value of your portfolio should not change. But, what is the derivative of a portfolio?  It's the instantaneous rate of change of the portfolio) relative to some underlying phenomenon.  With a portfolio of many stocks, there's not one single factor that drives the value of your portfolio. You have sensitivity to each underlying stock (price and volatility), interest rates, the market as a whole, etc. For simplicity, we might imagine a portfolio that has holdings in .... a call .... a stock .... and a bank account (to borrow and lend money).  You will have a delta relative to the stock and a delta relative to the underlying instrument on the option, etc.  Those can only be aggregated for each factor (e.g. if the call is an option on the same stock) Theta is the only one you can calculate for the portfolio as a whole - it will be the aggregate theta of all of your positions (since change in time is constant across all investments).  All of the others are not aggregatable since they are measuring sensitivities to different phenomena.