How splits and dividends affect option prices
"Investopedia explains how a stock split impacts the stock's options: Each option contract is typically in control of 100 shares of an underlying security at a predetermined strike price. To find the new coverage of the option, take the split ratio and multiply by the old coverage (normally 100 shares). To find the new strike price, take the old strike price and divide by the split ratio. Say, for example, you own a call for 100 shares of XYZ with a strike price of $75. Now, if XYZ had a stock split of 2 for 1, then the option would now be for 200 shares with a strike price of $37.50. If, on the other hand, the stock split was 3 for 2, then the option would be for 150 shares with a strike price of $50. So, yes, a 2 for 1 stock split would halve the option strike prices.  Also, in case the Investopedia article isn't clear, after a split the options still control 100 shares per contract. Regarding how a dividend affects option prices, I found an article with a good explanation: As mentioned above, dividends payment could reduce the price of a stock due to reduction of the company's assets. It becomes intuitive to know that if a stock is expected to go down, its call options will drop in extrinsic value while its put options will gain in extrinsic value before it happens. Indeed, dividends deflate the extrinsic value of call options and inflate the extrinsic value of put options weeks or even months before an expected dividend payment.  Extrinsic value of Call Options are deflated due to dividends not only because of an expected reduction in the price of the stock but also due to the fact that call options buyers do not get paid the dividends that the stock buyers do. This makes call options of dividend paying stocks less attractive to own than the stocks itself, thereby depressing its extrinsic value. How much the value of call options drop due to dividends is really a function of its moneyness. In the money call options with high delta would be expected to drop the most on ex-date while out of the money call options with lower delta would be least affected. If a stock is expected to drop by a certain amount, that drop would already have been priced into the extrinsic value of its put options way beforehand. This is what happens to put options of dividend paying stocks. This effect is again a function of options moneyness but this time, in the money put options raise in extrinsic value more than out of the money put options. This is because in the money put options with delta of close to -1 would gain almost dollar or dollar on the drop of a stock. As such, in the money put options would rise in extrinsic value almost as much as the dividend rate itself while out of the money put options may not experience any changes since the dividend effect may not be strong enough to bring the stock down to take those out of the money put options in the money. So, no, a dividend of $1 will not necessarily decrease an option's price by $1 on the ex-dividend date.  It depends on whether it's a call or put option, and whether the option is ""in the money"" or ""out of the money"" and by how much."
The adjusted close price takes into account stock splits (and possibly dividends). You want to look at the adjusted close price. Calculating percentage changes gets computationally tricky because you need to account for splits and dividends. It was actually a reverse split meaning that every 10 shares you had became 1 share and the price should be 10x higher. - Citigroup in reverse split The chart just accounts for the split. The big dip is Googles way of showing from what price it split from. If you remember before the split the stock was trading around $4-$5 after the reverse split the stock became 10x higher. Just to clear it up a 1:2(1 for 2) split would mean you get 1 share for every 2 shares you have. This is known as a reverse split.  A 2:1(2 for 1) split means you get 2 shares for every 1 share you have. The first number represents the amount of shares you will receive and the second number represents how many shares you will be giving up. Put options are contracts to sell. You pay me a fee for the right to put the stock (or other underlying security) in my hands if you want to. That happens on a specific date (the strike date) and a specified price (the strike price). You can decide not to exercise that right, but I must follow through and let you sell it to me if you want to. Put options can be used by the purchaser to cap losses. For example: You purchase a PUT option for GE Oct19 13.00 from me. On October 19th, you can make me let you sell your GE stock to me for $13.00 a share. If the price for GE has fallen to $12.00, that would be a good idea. If its now at $15.00 a share, you will probably keep the GE or sell it at the current market price. Call options are contracts to buy. The same idea only in the other direction: You pay me a fee for the right to call the stock away from me. Calls also have a strike date and strike price. Like a put, you can choose not to exercises it. You can choose to buy the stock from me (on the strike date for the strike price), but I have to let you buy it from me if you want to.  For example: You purchase a CALL option for GE Oct19 16.00 option from me. On October 19th, you can buy my GE stock from me for $16.00 a share. If the current price is $17.50, you should make me let you buy if from me for $16.00. If its less than $16.00, you could by it at the current market price for less. Commonly, options are for a block of 100 shares of the underlying security. Note: this is a general description. Options can be very complicated. The fee you pay for the option and the transaction fees associated with the shares affects whether or not exercising is financially beneficial. Options can be VERY RISKY. You can loose all your money as there is no innate value in the option, only how it relates to the underlying security. Before your brokerage will let you trade, there are disclosures you must read and affirm that you understand the risk. "The share price on its own has little relevance without looking at variations. In your case, if the stock went from 2.80 to 0.33, you should care only about the 88% drop in value, not what it means in pre-split dollar values. You are correct that you can ""un-split"" to give you an idea of what would have been the dollar value but that should not give you any more information than the variation of 88% would. As for your title question, you should read the chart as if no split occurred as for most intents and purposes it should not affect stock price other than the obvious split." "All else being equal, you should look for more volatile (riskier) stocks. Technically, it was all time value - the entire value of an ""out of the money"" option is time value.   What's confusing is that time value is affected by numerous variables, only one of which is time. The reason volatility is the one to look at is that all the rest are likely already intuitive to you, or are too minor an influence to worry about: Current risk-free interest rates and a stock's dividend payout during the life of the option affect the value of the call, but are usually minor infulences.   (Higher interest rates makes call values higher, and higher dividend yield makes call values lower.) Longer time to expiration will increase the value of the call, but you're pretty likely already focused on that. The strike price's proximity to the current price affects the call's value - agreeing to sell a stock 5% above current levels will pay more than agreeing to sell it 10% above current levels - but again, this is likely obvious to you. Volatility, or the percent by which the stock is likely to move up or down on a given day, is almost certainly the variable that's not already obvious. Stocks that jump all over the place have higher volatility than those that move more predictably.     The reason that options (calls and puts) cost more on higher volatility names is that options' payout is asymmetrical.  In the case of calls, the option holder gets all the upside, but none of the downside, other than what they paid for the opotion.     If one stock goes up or down $5 every day, and another goes up or down $20 every day and you could pay some fixed amount to get that stock's upside, but not have any exposure to its downside, other than that fixed amount, you'd pay more for the one that pays you $20 or $0 than you would for the one that pays you $5 or $0.    That's why higher volatility (meaning larger daily moves) makes optimum prices higher." It's an artifact of risk-neutral pricing, but the intuition is this:  A call option can be viewed as a levered equity position - meaning, you can get the same exposure by borrowing money and buying the stock.    Say you can buy some call options for $150 with a position delta of 1 (so it looks just like the stock).  You could also buy the stock outright for $1000 (by borrowing $850 at the risk-free rate and using your $150 cash).  If the risk-free rate rises, your cost of carry on the stock position increases.  In the case of the call option, the change in price can be viewed as the cost of *leverage* increasing. "In addition to the other answers it's also noteworthy that the stock exchanges themselves adjust the price quotes via their ex-div mechanism.  All limit orders present in the book when the stock goes ex-div will be adjusted by the dividend. Which means you can't even get ""accidentally"" filled in the very unlikely case that everyone forgot to adjust their quotes." One broker told me that I have to simply read the ask size and the bid size, seeing what the market makers are offering. This implies that my order would have to match that price exactly, which is unfortunate because options contract spreads can be WIDE. Also, if my planned position size is larger than the best bid/best ask, then I should break up the order, which is also unfortunate because most brokers charge a lot for options orders.