Why is volatility in a positive direction clubbed in the same risk category as volatility in a negative direction?
Mostly, when an equity's price rises, its statistical and implied volatilities fall and vice versa. The reason why is a mathematical phenomenon mixed with the reality that a unceasingly falling asset price will soon not exist, skewing the results with survivorship bias.   Since volatility is standard deviation of price indexes, a security that changes in price by the same amount every day will have lower volatility, so a rising price will have lower implied volatility because its mostly experiencing positive daily price change while a recently falling price will have higher volatility because factored together with the positive price changes, the negative price changes will widen the standard deviation of the securities price index. Quantitatively, any change, in or out of one's favor, is a risk because change is uncertain, and any uncertainty is a risk. This quantitative interpretation while valid runs almost totally counter to the value opinion, that a lower price relative to value is a lower risk than a higher price relative to value, but both have their place in time. Over long time periods, it's best to use the value interpretation, quantitative for shorter.  Using the opposite has hastily destroyed many a fund manager.
If upper and bollinger bands either converge (both bands are getting more and more close together) or diverge (both bands are getting more and more away from each other), does that mean the market is TRENDING? The answer is no. The divergence or convergence of BB-upper & lower band does not indicate if the market is trending or not. It only indicated if volatility is increasing or decreasing. Or is market trending only in case if both bands, upper and lower, are parallel and at the same time NOT horizontal? The answer is yes. To understand the reason consider that BB is constructed from a central Moving Average along with standard deviation. Upper Band=MA+2*SD, Lower Band=MA-2*SD. A moving average is a trend following indicator and volatility has nothing to do with trend (as SD only measures the price movement around the mean). Which essentially means BB has trend following qualities. The upper and lower bands remain more or less parallel in between band contraction and expansion. Refer below:   You shall see distinctly phases when BB bands are not parallel and are parallel and not horizontal. As mentioned above, when BB bands are expanding or contracting they do not give indication of the trend direction. When they are parallel, close or apart and not horizontal, they provide a good directional bias through the general slope. Though a more effective method to determine trend and its direction is the central MA of BB. Again, refer below:  Here you can see that some portion of the bands are parallel and more or less horizontal. The price action would tell you that the stock is now range-bound as opposed to trending. The primary use of the BB bands are to gauge volatility as @misantroop stated. The primary trend direction is usually derived from the central MA. If you do not understand the volatility of the fx market, you need to stop trading it, immediately. There are many reasons that fx is riskier than other types of investing, and you bear those risks whether you understand them or not. Below are a number of reasons why fx trading has high levels of risk: 1) FX trades on the relative exchange rate between currencies. That means it is a zero-sum game. Over time, the global fx market cannot 'grow'. If the US economy doubles in size, and the European economy doubles in size, then the exchange rate between the USD and the EUR will be the same as it is today (in an extreme example, all else being equal, yes I know that value of currency /= value of total economy, but the general point stands).  Compare that with the stock market - if the US economy doubles in size, then effectively the value of your stock investments will double in size. That means that stocks, bonds, etc. tied to real world economies generally increase when the global economy increases - it is a positive sum game, where many players can be winners. On the long term, on average, most people earn value, without needing to get into 'timing' of trades. This allows many people to consider long-term equity investing to be lower risk than 'day-trading'. With FX, because the value of a currency is in its relative position compared with another currency, 1 player is a winner, 1 player is a loser. By this token, most fx trading is necessarily short-term 'day-trading', which by itself carries inherent risk. 2) Fx markets are insanely efficient (I will lightly state that this is my opinion, but one that I am not alone in holding firmly). This means that public information about a currency [ie: economic news, political news, etc.] is nearly immediately acted upon by many, many people, so that the revised fx price of that currency will quickly adjust. The more efficient a market is, the harder it is to 'time a trade'. As an example, if you see on a news feed that the head of a central bank authority made an announcement about interest rates in that country [a common driver of fx prices], you have only moments to make a trade before the large institutional investors already factor it into their bid/ask prices. Keep in mind that the large fx players are dealing with millions and billions of dollars; markets can move very quickly because of this. Note that some currencies trade more frequently than others. The main currency 'pairs' are typically between USD and / or other G10 country-currencies [JPY, EUR, etc.]. As you get into currencies of smaller countries, trading of those currencies happens less frequently. This means that there may be some additional time before public information is 'priced in' to the market value of that currency, making that currency 'less efficient'. On the flip side, if something is infrequently traded, pricing can be more volatile, as a few relatively smaller trades can have a big impact on the market.  3) Uncertainty of political news. If you make an fx trade based on what you believe will happen after an expected political event, you are taking risk that the event actually happens. Politics and world events can be very hard to predict, and there is a high element of chance involved [see recent 'expected' election results across the world for evidence of this]. For something like the stock market, a particular industry may get hit every once in a while with unexpected news, but the fx market is inherently tied to politics in a way that may impact exchange rates multiple times a day. 4) Leveraging. It is very common for fx traders to borrow money to invest in fx. This creates additional risk because it amplifies the impact of your (positive or negative) returns. This applies to other investments as well, but I mention it because high degrees of debt leveraging is extremely common in FX. To answer your direct question: There are no single individual traders who spike fx prices - that is the impact you see of a very efficient market, with large value traders, reacting to frequent, surprising news.  I reiterate: If you do not understand the risks associated with fx trade, I recommend that you stop this activity immediately, at least until you understand it better [and I would recommend personally that any amateur investor never get involved in fx at all, regardless of how informed you believe you are]. "The main difference between a bull market and a bear market is due the ""the leverage effect"". http://www.princeton.edu/~yacine/leverage.pdf The leverage effect refers to the observed tendency of an asset’s   volatility to be negatively correlated with the asset’s returns.   Typically, rising asset prices are accompanied by declining   volatility, and vice versa. The term “leverage” refers to one possible   economic interpretation of this phenomenon, developed in Black (1976)   and Christie (1982): as asset prices decline, companies become   mechanically more leveraged since the relative value of their debt   rises relative to that of their equity. As a result, it is natural to   expect that their stock becomes riskier, hence more volatile. More volatile assets in a bear market are not such good investments as less volatile assets in a bull market." "What is being described in Longson's answer, though helpful, is perhaps more similar to a financial spread bet. Exactly like a bookmaker, the provider of a spread bet takes the other side of the bet, and is counter party to your ""trade"". A CFD is also a bet between two parties. Now, if the CFD provider uses a market maker model, then this is exactly the same as with a spread bet and the provider is the counter party. However, if the provider uses a direct market access model then the counter party to your contract is another CFD trader, and the provider is just acting as an intermediary to bring you together (basically doing the job of both a brokerage and an exchange). A CFD entered into through a direct market access provider is in many ways similar to a Futures contract. Critically though, the contract is traded 'over-the-counter' and not on any centralized and regulated exchange. This is the reason that CFDs are not permitted in the US - the providers are not authorized as exchanges. Whichever model your CFD provider uses, it is best to think of the contract as a 'bet' on the future price movements of the underlying stock or commodity, in much the same way as with any other derivative instrument such as futures, forwards, swaps, or options. Finally, note that because you don't actually own the underlying stock (just as Longson has highlighted) you won't be entitled to any of the additional benefits that can come with ownership of a stock, such as dividend payments or the right to attend shareholder meetings. RESPONSE TO QUESTION So if I understand correctly, the money gained through a direct market access model comes from other investors in the same CFD who happened to have invested in the ""wrong"" direction the asset was presumed to take. What happens then, if no one is betting in the opposite direction of my investment. Your understanding is correct. If literally nobody is betting in the opposite direction to you, then you will not be able to trade. This is true for any derivative market; if suddenly every single buyer were to remove their bids from the S&P futures, then no seller would be able to sell. This is a very extreme scenario, as the S&P futures market is incredibly liquid (loads of buyers and sellers at all times).  However, if something like this does happen (the flash crash of 2010, for example), then the centralized futures exchanges such as the CME have safeguards in place - the market become locked-limit so that it can only fall so far, there may be no buyers below the lock limit price, but the market cannot fall through it. CFD providers are not obliged to provide such safeguards, which is why regulators in the US don't permit them to operate. It may be the case that if you're trying to buy a CFD for a thinly traded and ill-liquid stock there will be no seller available. One possibility is that the provider will offer a 'hybrid' model, and in the absence of an independent counter party they will take the opposite side of your bet, and then offset their risk by taking an opposing position in the underlying stock." I use over half my buying power of my portfolio for options, and I'm not a fan of any of the strategies listed above either (I stay away from negative theta trades for the most part), but I just listed them to point out that saying the reason someone wouldn't enter a short position is for fear of infinite losses is asinine. It's easy enough to make any trade risk defined if that is something the trader cares about. Options pricing is based on the gap between strike and the current market, and volatility. That's why the VIX, a commonly accepted volatility index, is actually just a weighted blend of S&P 500 future options prices.  A general rise in the price of options indicates people don't know whether it will go up or down next, and are therefore less willing to take that risk.  But your question is why everything underwater in the puts chain went higher, and that's simple: now that Apple's down, the probability of falling a few more points is higher. Especially since Apple has gone through some recent rough times, and stocks in general are seen as risky these days. Equal weighted indexes are not theoretically meant to be less volatile or less risky; they're just a different way to weigh stocks in an index. If you had a problem that hurt small caps more than large caps, an equal weighted index will be hurt more than a market-cap weighted one.  On the other hand, if you consider that second rung companies have come up to replace the top layer, it makes sense to weigh them on par.  History changes on a per-country basis - in India, for instance, the market's so small at the lower-cap end that big money chases only the large caps, which go up more in a liquidity driven move. But in a more secular period (like the last 18 months) we see that smaller caps have outperformed. The market moves faster than ratings agencies.  Everyday the market is trying to figure out the true value of Assets - Liabilities and thus its overall equity value.  The financial crisis illustrated this perfectly when Bear Sterns got stuck in a liquidity trap.  It's MBS(CDO) was still highly rated, likewise its overall credit rating was sound, however in reality the value of assets were much higher due to coming default, credit providers realized assets Bear had posted as collateral were falling in value quickly.  This started the death spiral, or feedback loop in which it isn't clear if the tail wagged the dog or the dog wagged the tail, but as equity value fell Bear could no longer get access to credit markets to fund daily operations, once it got margin called and couldn't pay, it was all over.  When it was sold to JPM, they basically stole the entire company at a fire sale price, everyone knew they were getting a deal, as reflected in the post buyout price jump of JPM stock.    So in a technical sense you are right, they have nothing to do with each other.  But in a practical sense as we see equity value collapse we are approaching bankruptcy, and thus default, and credit ratings should represent likelihood of default so the two should have a positive correlation to one another, assuming equity value is the 'true value'.