Why do more floating shares mean less volatility for the stock?
More shares mean less volatility because it takes a larger number of trades, a larger number of shares per trade, or a combination of both to raise or lower the stock price. Institutional investors (mutual funds, pensions, hedge funds, other investment firms, etc) are the sorts of organizations with the large amounts of money needed to move a stock price one way or the other.  But the more floating shares there are in a company, the harder it is for one or two firms to move a stock price.  A company with fewer floating shares wouldn't require as many trades (or as many shares per trade) to see wider swings in price. When it comes to stock price, insider trading isn't the same as manipulation.  In the (surprisingly few) cases of insider trading that are prosecuted, it tends to be an individual (or small group) with early access to information that the broader market doesn't have being able to buy or sell ahead of the broader market.  Their individual sales are seldom if ever enough to noticeably move a stock price.  They're locking in profit or limiting a loss.  Manipulation might (but doesn't always) precede insider trading, if misinformation (or truth) is released for the purpose of creating a situation that can be profited from via a trade or trades.
This happens on dark pools quite often. If I am a large institutional investor with tens of millions of shares, I may want to unload slowly and limit the adverse affects on the price of the stock. Dark pools offer anonymity and have buyers / sellers that can handle large volume.  In the case of a day trader, they often trade stocks with light volume (since they have large fluctuations that can be quite profitable throughout the session). At the end of the session, many traders are unwilling to hold positions on margin and want to unload fast. As others have posted, the company gains capital in return for its new shares. However, the share price can still fall. The problem is that the share marked is affected by supply and demand like any other marked.  If the company just issues the new shares at marked price, they will have problems finding buyers.  The people who are willing to pay that price has already bought as many shares as they want. The company does this to raise capital, and depends on the shares actually selling for this to work.  So, they issue shares at below marked price to attract buyers and the shares get diluted.  In the end the share will usually end up somewhere between the old marked price and the issue price. The old share owners are probably not too happy about this and will not accept this plan. (At least here in Norway, share issue has to be accepted at a shareholder meeting) So, what is often done instead is to issue buy options for the required number of shares at the below-marked price.  These options are given (for free) to the current share holders proportional to their current holding. If everybody exercises their options they get new cheap shares that compensates for the loss of share value.  If they don't have the capital themselves, they can sell the options and get compensation that way instead. Changes in implied volatility are caused by many things, of course, and it is tough to isolate the effect you are describing, but let's try to generalize for a moment. Implied volatility is generally a measure of how much expect uncertainty there is about the future price of the stock.  Uncertainty generally is higher in periods including earnings announcements because it is significant new information about the company's fortunes can make for significant changes in the price. However, you could easily have the case where the earnings are good and for some reason the market is very certain that the earnings will be good and near a certain level.  In that case the price would rise, but the implied volatility could well be lower because the market believes that there will be no significant new information in the earnings announcement. Or you owned one that was bought out, so you got a ~30% return + whatever else the stock had returned prior to that. Everyone is pushing for the companies they hold to be bought for a quick paycheck, so you're seeing fewer companies... I don't know why stocks in some industries tend to have lower prices per share than others. It doesn't really matter much. Whether a company has 1,000,0000 shares selling for $100 each, or 10,000,000 shares selling for $10 each, either way the total value is the same. Companies generally like to keep the share price relatively low so that if someone wants to buy a small amount, they can. Like if the price was $10,000 per share, than an investor with less than $10,000 to put in that one stock would be priced out of the market. If it's $10, then if someone wants $10 they can buy one share, and if someone wants $10,000 they can buy 1000 shares. As to why energy stocks are volatile, I can think of several reasons. One, in our current world, energy is highly susceptible to politics. A lot of the world's energy comes from the Middle East, which is a notoriously unstable region. Any time there's conflict there, energy supplies from the region become uncertain. Oil-producing countries may embargo countries that they don't like. A war will, at the very least, interfere with transportation and shipping, and may result in oil wells being destroyed. Etc. Two, energy is consumed when you use it, and most consumers have very limited ability to stockpile. So you're constantly buying the energy you need as you need it. So if demand goes down, it is reflected immediately. Compare this to, say, clothing. Most people expect to keep the same clothes for years, wearing them repeatedly. (Hopefully washing them now and then!) So if for some reason you decided today that you only need three red shirts instead of four, this might not have any immediate impact on your buying. It could be months before you would have bought a new red shirt anyway. There is a tendency for the market to react rather slowly to changes in demand for shirts. But with energy, if you decide you only need to burn 3 gallons of gas per week instead of 4, your consumption goes down immediately, within days. Three, really adding to number two, energy is highly perishable, especially some forms of energy. If a solar power station is capable of producing 10 megawatts but today there is only demand for 9 megawatts, you can't save the unused megawatt for some future time when demand is higher. It's gone. (You can charge a battery with it, but that's pretty limited.) You can pile up coal or store natural gas in a tank until you need it, but you can't save the output of a power plant. Note numbers two and three also apply to food, which is why food production is also very volatile. What is your investment goal?  Many investors buy for the long haul, not short-term gain.  If you're looking for long-term gain then daily fluctuations should be of no concern to you.  If you want to day-trade and time the market (buy low and sell high with a short holding period) then yes less volatile stock can be less profitable, but they also carry less risk.  In that case, though, transaction fees have more of an impact, and you usually have to trade in larger quantities to reduce the impact of transaction fees. "The simple answer could be that one or more ""people"" decided to buy. By ""people,"" I don't mean individual buyers of 100 shares like you or me, but typically large institutional investors like Fidelity, who might buy millions of shares at a time. Or if you're talking about a human person, perhaps someone like Warren Buffett. In a ""thinly"" traded small cap stock that typically trades a few hundred shares in a day, an order for ""thousands"" could significantly move the price. This is one situation where more or less ""average"" people could move a single stock." Ok, so disregarding passivity, could you help me through a simplified example?   Say I only had two assets, SPY and TLT, with a respective weight of 35 and 65% and I want want to leverage this to 4x.  Additionally, say daily return covar is:  * B/B .004% * B/S -.004% * S/S .02%   Now, if I read correctly, I should buy ATM calls xxx days in the future.  Which may look like: Ticker, S, K, Option Price, Delta, Lambda  * TLT  $126.04  $126.00  $4.35  0.50  14.5 * SPY  $134.91  $134.00  $6.26  0.55  11.8  ^ This example is pretty close but some assets are far off.   I feel like I'm on the wrong track so I'll stop here.    I just want to lever up my risk-parity. Margin rates are too high and I'm docked by Reg-T. Say the company has created 500 shares [or whatever number]. You have 10 shares [equivalent of 2%]. Now when new capital is needed, generally more shares are created. Say they create 100 more shares and sell it to venture capital to raise funds. After this happens; Total Shares: 500+100 = 600 You own: 10 shares Your Ownership % = 1.66% down from 2% Like wise for other older shareholder. The New Venture guy gets 16.66% of ownership.   More funds would mean more growth and overall the value of your 10 shares would be more depending on the valuation. Like others have already said, it may cause an immediate dip due to a large and sudden move in shares for that particular stock. However, if there is nothing else affecting the company's financials and investors perceive no other risks, it will probably bounce back a bit, but not back to the full value before the shares were issued. Why? Whenever a company issues more stock, the new shares dilute the value of the current shares outstanding, simply because there are now more shares of that stock trading on the market; the Earnings Per Share (EPS) Ratio will drop since the same profit and company value has to be spread across more shares. Example:  If a company is valued at $100 dollars and they have 25 shares outstanding, then the EPS ratio equates to $4 per share (100/25 = 4).  If the company then issues more shares (stock to employees who sell or keep them), let's say 25 more shares, then shares outstanding increase to 50, but the company's value still remains at $100 dollars. EPS now equates to $2 per share (100/50 = 2). Now, sometimes when shareholders (especially employees...and especially employees who just received them) suddenly all sell their shares, this causes a micro-panic in the market because investors believe the employees know something bad about the company that they don't. Other common shareholders then want to dump their holdings for fear of impending collapse in the company. This could cause the share price to dip a bit below the new diluted value, but again if no real, immediate risks exist, the price should go back up to the new, diluted value. Example 2: If EPS was at $4 before issuing more stock, and then dropped to $2 after issuing new stock, the micro-panic may cause the EPS to drop below $2 and then soon rebound back to $2 or more when investors realize no actual risk exists. After the dilution phase plays out, the EPS could actually even go above the pre-issuing value of $4 because investors may believe that since more stock was issued due to good profits, more profits may ensue. Hope that helps! Also important to keep in mind is the difference in liquidity. The stock could be very liquid in 1 exchange but not in another. When times get bad, liquidity could dry up 1 one exchange, which results in a trading discount. The future shares will be fewer in number, yet have claim to less cash in the bank. All in all, there's little reason the shares would rise in value.  Say there are 1M shares, trading at $10. Market cap is $10M of course. Now, there happens to be $2M cash in the bank so each share had about $2 cash. By taking the $2M and buying 200K shares, 800K shares remain, but why would you think they'd be valued at $12.50? The same $10 value per share is now an $8M market cap as $2M has been disbursed, no less so than if it were given out in a dividend. "The calculation and theory are explained in the other answers, but it should be pointed out that the video is the equivalent of watching a magic trick.  The secret is: ""Stock A and B are perfectly negatively correlated.""  The video glasses over that fact that without that fact the risk doesn't drop to zero. The rule is that true diversification does decrease risk. That is why you are advised to spread year investments across small-cap, large-cap, bonds, international, commodities, real estate. Getting two S&P 500 indexes isn't diversification.  Your mix of investments will still have risk, because return and risk are backward calculations, not a guarantee of future performance. Changes that were not anticipated will change future performance. What kind of changes: technology, outsourcing, currency, political, scandal." "people are willing to pay higher premiums for options when stocks go down. Obviously the time value and intrinsic value and interests rates of the option doesn't change because of this so the miscalculation remainder is priced into the implied volatility part of the formula.  Basically, anything that suggests the stock price will get volatile (sharp moves in either direction) will increase the implied volatility of the option. For instance, around earnings reports, the IV in both calls and puts in the nearest expiration dates are very high. When stocks go down sharply, the volatility is high because some people are buying puts for protection and others are buying calls because they think there will be a rebound move in the other direction. People (the ""sleep-at-night"" investors, not the derivatives traders ;) )  tend to be calm when stocks are going up, and fearful when they are going down. The psychology is important to understand and observe and profit from, not to quantitatively prove. The first paragraph should be your qualitative answer" Consider the case where a stock has low volume.  If the stock normally has a few hundred shares trade each minute and you want to buy 10,000 shares then chances are you'll move the market by driving up the price to find enough sellers so that you can get all those shares.  Similarly, if you sell way more than the typical volume, this can be an issue.