Is there any reason to buy shares before/after a split?
Assuming you plan to buy a whole number of shares and have a maximum dollar value you intend to invest, it may be better to wait for the split if the figures don't quite work out nicely. For example, if you are going to invest $1,000 and the stock pre-split is $400 and the split is 2 for 1, then you'd buy 2 shares before the split unless you have an extra $200 to add. Meanwhile, after the split you could buy 5 shares at $200 so that you invest all that you intend. Aside from that case, it doesn't really make a difference since the split is similar to getting 2 nickels for a dime which in each case is still a total value of 10 cents. There has been a lot of research on the effects of stock splits. Some studies have concluded that: However note that (i) these are averages over large samples and does not say it will work on every split and (ii) most of the research is a bit dated and more recent papers have often struggled to find any significant performance impact after 1990, possibly because the effect has been well documented and the arbitrage no longer exists. This document summarises the existing research on the subject although it seems to miss some of the more recent papers. More practically, if you pay a commission per share, you will pay more commissions after the split than before. Bottom line: don't overthink it and focus on other criteria to decide when/whether to invest.
Most of the time when a stock splits to create more shares, it is done to bring the price per share down to a level that makes potential investors more comfortable. There are psychological reasons why some companies keep the price in the $30 to $60 range. Others like to have the price keep rising into the hundreds or thousands a share.  The split doesn't help current investors, with the possible exception that the news spurs interest in the stock which leads to a short term rise in prices; but it also doesn't hurt current investors. When a reverse stock split is done, the purpose is for one of several reasons: "I have heard that investing more money into an investment which has gone down is generally a bad idea*. ""Throwing good money after bad"" so to speak. This is over simplified statement to explain the concept. What is essentially says is; Say I hold stocks of XYZ; 100 units worth say USD 1000. This has lost me x% [say 50%]. The general tendency is to buy 100 more units in anticipation / hope that the price will go up. This is incorrect.  However on case to case basis, this maybe the right decisions. On a periodic basis [or whenever you want to invest more money]; say you have USD 1000 and did not have the stock of XYZ, will you buy this at current price and outlook of the company. If the answer is Yes, hold the stock [or buy more], if the answer is no sell the stock at current market price and take the loss. The same applies when the price has appreciated. If you have USD 1000; given the current price and future outlook, will you buy the specific stock. If yes, hold the stock [or buy more], if answer is no sell the stock and book profit. Off-course I have not overlaid the various other considerations when buying stocks like diversification, risk profiles of individual stocks / segments, tax implications etc that are also essential even if you decide to buy or sell specific stock." "The ex indicator is meant to be a help for market participants.  On the ex-day orders will go into a different order book, the ex order book, which at the start of the ex day will be totally empty, i.e. no orders from the non-ex day book have been copied over. Why does this help?  Well imagine you had a long-standing buy order in the book, well below the current price, and now the share price halves due to a 2-for-1 split, would you want to see your order executed? If so, your order should have gone into the ex-book which is only active on the ex-day (and orders in the ex book are usually copied over to the normal book on the day after the ex-day but this is exchange-specific). Think of it as an additional safety net to tell the exchange: ""I know what I'm doing: I want to buy this stock totally overpriced after the 2-for-1 split"". Now some exchanges and/or some securities (mostly derivatives) linked with the security in question don't have this notion of ex or the ex-book, and they will tell you by ""will not be quoted ex"" or ""the ex indicator is missing"". In your case (SNE) it is a sponsored ADR, the ex-date was Mar 28 2016, one day before the ex date of the Japanese original.  According to my understanding of NYSE rules, there is no specific rule for or against omitting the ex-indicator.  It seems to be a decision on a case by case basis.  Looking through the dividends of other Japanese ADRs I drew the conclusion none of them have an ex-book and so all of them are announced as: ""Will not be quoted ex by the exchange"".  Again, this is based on my observations." During a stock split the only thing that changes is the number of shares outstanding.  Typically a stock splits to lower its price per share.  Sometimes if a company's value is falling it will do a reverse split where X shares will be exchanged for Y shares.  This is typically done to avoid being de-listed from an exchange if the price per share falls below a certain threshold, usually $1.  Again the only thing changing is the number of shares outstanding.  A 20 for 1 reverse split means for every 20 shares outstanding the shareholder will be granted one new share. Example X Co. has 1,000,000 shares outstanding for a price of $100 per share.  It does a 1 for 10 split.  Now there are 10,000,000 shares outstanding for a price of $10 per share. Example Y Co has 1,000,000 shares outstanding for a price of $1 per share.  It does a 10 for 1 reverse split.  Now there are 100,000 shares outstanding for a price of $10. Quickly looking at the news for ASTI it looks like it underwent a 20 for 1 reverse split.  You should probably look at your statements and ask your broker how the arithmetic worked in your case. Investopedia links for Reverse Stock Split and Stock Split It depends on the timing of the events. Sometimes the buying company announces their intention but the other company doesn't like the deal. It can go back and forth several times, before the deal is finalized. The specifics of the deal determine what happens to the stock: The deal will specify when the cutoff is. Some people want the cash, others want the shares.  Some will speculate once the initial offer is announced where the final offer (if there is one) will end up. This can cause a spike in volume, and the price could go up or down. Regarding this particular deal I did find the following: http://www.prnewswire.com/news-releases/expedia-to-acquire-orbitz-worldwide-for-12-per-share-in-cash-300035187.html Additional Information and Where to Find It Orbitz intends to file with the SEC a proxy statement as well as other   relevant documents in connection with the proposed transaction with   Expedia. The definitive proxy statement will be sent or given to the   stockholders of Orbitz and will contain important information about   the proposed transaction and related matters. SECURITY HOLDERS ARE   URGED TO READ THE PROXY STATEMENT CAREFULLY WHEN IT BECOMES AVAILABLE   AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY   AMENDMENTS OR SUPPLEMENTS TO THOSE DOCUMENTS, BECAUSE THEY WILL   CONTAIN IMPORTANT INFORMATION. The proxy statement and other relevant   materials (when they become available), and any other documents filed   by Expedia or Orbitz with the SEC, may be obtained free of charge at   the SEC's website, at www.sec.gov. In addition, security holders will   be able to obtain free copies of the proxy statement from Orbitz by   contacting Investor Relations by mail at ATTN: Corporate Secretary,   Orbitz Worldwide, Inc., 500 W. Madison Street, Suite 1000, Chicago,   Illinois 60661. "Also note that a share of voting stock is a vote at the stockholder's meeting, whether it's dividend or non-dividend. That has value to the company and major stockholders in terms of protecting their own interests, and has value to anyone considering a takeover of the company or who otherwise wants to drive the company's policy. Similarly, if the company is bought out, the share will generally be replaced by shares in whatever the new owning company is. So it really does represent ""a slice of the company"" in several vary practical ways, and thus has fairly well-defined intrinsic value linked to the company's perceived value. If its price drops too low the company becomes more vulnerable to hostile takeover, which means the company itself will often be motivated to buy back shares to protect itself from that threat. One of the questions always asked when making an investment is whether you're looking for growth (are you hoping its intrinsic value will increase) or income (are you hoping it will pay you a premium for owning it). Non-dividend stocks are a pure growth bet. Dividend-paying stocks are typically a mixture of growth and income, at various trade-off points. What's right for you depends on your goals, timeframe, risk tolerance, and what else is already in your portfolio." "In Second Opinion's opinion, they say ""Do not initiate new position.""  This means do not buy the stock if you do not already own it.   Since they also say to hold if you do own it, this is a very ""who knows what it will do"" neutral position (IMO)." Your broker should make you whole by adjusting the quantity of the underlying (see: http://www.schaeffersresearch.com/education/options-basics/key-option-concepts/dividends-stock-splits-and-other-option-contract-adjustments) but I would check with them that this will happen. You will then have an option on 4 times the underlying for each option. Unless the price has risen in the interim or you bought them after the split was announced you should not make a loss. "I have heard that investing more money into an investment which has   gone down is generally a bad idea*. ""Throwing good money after bad"" so   to speak. Is investing more money into a stock, you already have a stake in,   which has gone up in price; a good idea? Other things being equal, deciding whether to buy more stocks or shares in a company you're already invested in should be made in the same way you would evaluate any investment decision and -- broadly speaking -- should not be influenced by whether an existing holding has gone up or down in value. For instance, given the current price of the stock, prevailing market conditions, and knowledge about the company, if you think there is a reasonable chance that the price will rise in the time-period you are interested in, then you may want to buy (more) stock. If you think there is a reasonable chance the price will fall, then you probably won't want to buy (more) stock. Note: it may be that the past performance of a company is factored into your decision to buy (e.g was a recent downturn merely a ""blip"", and long-term prospects remain good; or have recent steady rises exhausted the potential for growth for the time being). And while this past performance will have played a part in whether any existing holding went up or down in value, it should only be the past performance -- not whether or not you've gained or lost money -- that affects the new decision. For instance: let us suppose (for reasons that seemed valid at the time) you bought your original holding at £10/share, the price has dropped to £2/share, but you (now) believe both prices were/are ""wrong"" and that the ""true price"" should be around £5/share. If you feel there is a good chance of this being achieved then buying shares at £2, anticipating they'll rally to £5, may be sound. But you should be doing this because you think the price will rise to £5, and not because it will offset the loses in your original holding. (You may also want to take stock and evaluate why you thought it a good idea to buy at £10... if you were overly optimistic then, you should probably be asking yourself whether your current decisions (in this or any share) are ""sound""). There is one area where an existing holding does come into play: as both jamesqf and Victor rightly point out, keeping a ""balanced"" portfolio -- without putting ""all your eggs in one basket"" -- is generally sound advice. So when considering the purchase of additional stock in a company you are already invested in, remember to look at the combined total (old and new) when evaluating how the (potential) purchase will affect your overall portfolio." "Yahoo's ""Adj Close"" data is adjusted for splits, but not for dividends. Despite Yahoo's webpage's footnote saying  *Close price adjusted for dividends and splits. we can see empirically that the ""Adj Close"" is only adjusted for splits. For example, consider Siemens from Jan 27, 2017 to Mar 15, 2017: The Adj Close adjusts for splits: On any particular day, the ""Adj Close"" is equal to the ""Close"" price divided by the cumulative product of all splits that occurred after that day. If there have been no splits after that day, then the ""Adj Close"" equals the ""Close"" price. Since there is a 2-for-1 split on Mar 14, 2017, the Adj Close is half the Close price for all dates from Jan 27, 2017 to Mar 13, 2017. Note that if Siemens were to split again at some time in the future, the Adj Close prices will be readjusted for this future split. For example, if Siemens were to split 3-for-1 tomorrow, then all the Adj Close prices seen above will be divided by 3. The Adj Close is thus showing the price that a share would have traded on that day if the shares had already been split in accordance with all splits up to today. The Adj Close does not adjust for dividends: Notice that Siemens distributed a $1.87 dividend on Feb 02, 2017 and ~$3.74 dividend on Jan 30, 2017. If the Adj Close value were adjusted for these dividends then we should expect the Adj Close should no longer be exactly half of the Close amount. But we can see that there is no such adjustment -- the Adj Close remains (up to rounding) exactly half the Close amount: Note that in theory, the market reacts to the distribution of dividends by reducing the trading price of shares post-dividend. This in turn is reflected in the raw closing price. So in that sense the Adj Close is also automatically adjusted for dividends. But there is no formula for this. The effect is already baked in through the market's closing prices." Here's a different take:  Look through the lists of companies  that offer shareholder perks. Here's one from Hargreaves Lansdown.  See if you can find one that you already spend money with with a low required shareholding where the perks would actually be usable.  Note that in your case, being curious about the whole thing and based in London, you don't have to rule out the AGM-based perks, unlike me. My reason for this is simple: with 3 out of 4 of the companies we bought shares in directly (all for the perks), we've made several times the dividend in savings on money we would have spent anyway (either with the company in which we bought shares or a direct competitor).  This means that you can actually make back the purchase price plus dealing fee quite quickly (probably in 2/4 in our case), and you still have the shares. We've found that pub/restaurant/hotel brands work well if you use them or their equivalents anyway. Caveats: It's more enjoyable than holding a handful of shares in a company you don't care about, and if you want to read the annual reports you can relate this to your own experience, which might interest you given your obvious curiosity. "This answer relies on why you are holding shares of a company in the first place. So let's address that: So does this mean you would like to vote with your shares on the directions the company takes? If so, your reasons for selling would be different from the next speculator who only is interested in share price volatility. Regardless of your participation in potential voting rights associated with your share ownership, a different reason to sell is based on if your fundamental reasons for investing in the company have changed.  Enhancements on this topic include: Trade management, how to deal with position sizes. Buying and selling partial positions based on price action while keeping a core long term position, but this is not something ""long term investors"" generally put too much effort in. Price targets, start your long term investment with a price target in mind, derived from a future market cap based on your initial fundamental analysis of the company's prospects. And finally, there are a lot of things you can do with a profitable investment in shares." "I'm not sure what you expect in terms of answers, but it depends on personal factors. It pretty well has to depend on personal factors, since otherwise everyone would want to do the same thing (either everyone thinks the current price is one to sell at, or everyone thinks it's one to buy at), and there would be no trades. You wouldn't be able to do what you want, except on the liquidity provided by market makers. Once that's hit, the price is shifting quickly, so your calculation will change quickly too. Purely in terms of maximising expected value taking into account the time value of money, it's all about the same. The market ""should"" already know everything you know, which means that one time to sell is as good as any other. The current price is generally below the expected acquisition price because there's a chance the deal will fall through and the stock price will plummet. That's not to say there aren't clever ""sure-fire"" trading strategies around acquisitions, but they're certain to be based on more than just timing when to sell an existing holding of stock. If you have information that the market doesn't (and assuming it is legal to do so) then you trade based on that information. If you know something the market doesn't that's going to be good for price, hold. If you know something that will reduce the price, sell now. And ""know"" can be used in a loose sense, if you have a strong opinion against the market then you might like to invest based on that. Nothing beats being paid for being right. Finally, bear in mind that expected return is not the same as utility. You have your own investment goals and your own view of risk. If you're more risk-averse than the market then you might prefer to sell now rather than wait for the acquisition. If you're more risk-prone than the market then you might prefer a 90% chance of $1 to 90c. That's fine, hold the stock. The extreme case of this is that you might have a fixed sum at which you will definitely sell up, put everything into the most secure investments you can find, and retire to the Caribbean. If that's the case then you become totally risk-averse the instant your holding crosses that line. Sell and order cocktails." Yes you can do that and it it wise to do so. However, you should make sure that the general trend of the stock is upwards and you buy during a trought in the uptrend. So basically if the stock is making higher highs and higher lows on the daily or weekly charts, then you would want to buy around one of the higher lows before the ex-dividend date. If the stock is making lower lows and lower highs, then it is in a downtrend, so never buy in this instance. It is better to miss out on a dividend of $1 rather than to buy just for this $1 dividend and lose $5 or more when the price continues to drop further. You guys seem to have forgotten the most important part of this equation ... i work for a bank and I can tell u this as a painful fact ... every business is governed by its paperwork ... articles bylaws operating agreements amendments and minutes .. if a companys paperwork says that the 51% owner can fire everyone and move to Alaska and that paperwork is proper (signed and binding) it is with minimal excavation law... case in point every company is different .. and it is formed and governed by its paperwork.