Accounting for splits in a stock price graph
One way that is common is to show the value over time of an initial investment, say $10,000.  The advantage of this is that it doesn't show stock price at all, so handles splits well.  It can also take into account dividend reinvestment.  Fidelity uses this for their mutual funds, as can be seen here.  Another option would be to compute the stock price as if the split didn't happen.  So if a stock does a 2:1 split, you show double the actual price starting at that point.
Unfortunately I believe there is not a good answer to this because it's not a well posed problem.  It sounds like you are looking for a theoretically sound criteria to decide whether to sell or hold.  Such a criteria would take the form of calculating the cost of continuing to hold a stock and comparing it to the transactions cost of replacing it in your portfolio. However, your criteria for stock selection doesn't take this form.  You appear to have some ad hoc rules defining whether you want the stock in your portfolio that provide no way to calculate a cost of having something in your portfolio you don't want or failing to have something you do want.  Criteria for optimally rebalancing a portfolio can't really be more quantitative than the rules that define the portfolio. Another one I have seen mentioned used is Equity Feed. It had varies levels of the software depending on the markets you want and can provide level 2 quotes if select that option. http://stockcharts.com/ is also a great tool I see mentioned with lots of free stuff. "ycharts.com has ""Weighted Average PE Ratio"" and a bunch of other metrics that are meant to correspond to well known stock metrics.  Other websites will have similar ratios." Have you actually read the Wikipedia article? To calculate the DJIA, the sum of the prices of all 30 stocks is divided by a divisor, the Dow Divisor. The divisor is adjusted in case of stock splits, spinoffs or similar structural changes, to ensure that such events do not in themselves alter the numerical value of the DJIA. Early on, the initial divisor was composed of the original number of component companies; which made the DJIA at first, a simple arithmetic average. The present divisor, after many adjustments, is less than one (meaning the index is larger than the sum of the prices of the components). That is: DJIA = sum(p) / d where p are the prices of the component stocks and d is the Dow Divisor. Events such as stock splits or changes in the list of the companies composing the index alter the sum of the component prices. In these cases, in order to avoid discontinuity in the index, the Dow Divisor is updated so that the quotations right before and after the event coincide: DJIA = sum(p_old) / d_old = sum(p_new) / d_new The Dow Divisor was 0.14602128057775 on December 24, 2015.[40] Presently, every $1 change in price in a particular stock within the average, equates to a 6.848 (or 1 ÷ 0.14602128057775) point movement. Knowing the old prices, new prices (e.g. following a split), and old divisor, you can easily compute the new divisor... Edit: Also, the detailed methodology is published by SP Indices (PDF). Edit #2: For simplicity's sake, assume the DJIA is an index that contains 4 stocks, with a price of $100.00 each. One of the stocks splits 2:1, meaning the new price/share is $50.00. Plugging the numbers into the above equation, we can determine the new Dow Divisor: 400 / 4 = 350 / d => d = 3.5 I dont know if this data is available for the 1980s, but this response to an old question of mine discusses how you can pull stock related information from google or yahoo finance over a certain period of time. You could do this in excel or google spreadsheet and see if you could get the data you're looking for.  Quote from old post: Google Docs spreadsheets have a   function for filling in stock and fund   prices. You can use that data to graph (fund1   / fund2) over some time period. Any time you are optimizing a portfolio, the right horizon to use for computing the statistics you will use for optimization (expected return, covariance, etc.) will be the same as your rebalance/trading frequency.  If you expect your trading strategy to trade once a day, you should use daily data for optimization.  Ditto for monthly or quarterly.  If at all possible you should use statistics across the board that are computed at the same frequency as your trading. Regarding currency pricing, I see no reason you can't take the reported prices and convert them to whatever currency you want using that day's foriegn exchange rate.  Foreign exchange rates are available for free at the Fed and elsewhere.  Converting prices from one currency to another is not rocket science. Since you are contemplating putting actual money behind this, note that using data to compute statistics is less reliable for lower statistical moments.  The mean (expected return) is the first moment, so using historical returns is extremely unreliable at predicting future returns.  The variances and covariances are second moments, they are better.  Skewness and kurtosis, yet better.  The fact that the expected return can't reliably be estimated from past returns is the major downfall of the Markowitz method (resulting portfolios are often very crazy and will depend critically on the data period you use to set them up).   There are approaches to fixing this, such as Black-Litterman's (1992) method, but they get complicated fast. 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. Haha, I used to work for a head of research whose favorite pastime seemed to be putting together these kinds of charts.  Edit: And the funny thing is people who take this chart at face value shouldn't want to short anyway - the balance sheet is going to flatline for sometime before they start letting it run off - so at most it suggests that people utilize strategies that work in sideways markets. This is fine, but I'd probably spend a moment introducing WACC and it's estimation. It's also useful to link up the enterprise value to share price, so just also mentioning the debt subtraction to get equity value and division by shares for price.  Keep in mind you're usually given like a minute to answer this, so you can afford to be a bit more detailed in some parts. James Roth provides a partial solution good for stock picking but let's speed up process a bit, already calculated historical standard deviations: Ibbotson, very good collection of research papers here, examples below Books "Their algorithm may be different (and proprietary), but how I would to it is to assume that daily changes in the stock are distributed normally (meaning the probability distribution is a ""bell curve"" - the green area in your chart).  I would then calculate the average and standard deviation (volatility) of historical returns to determine the center and width of the bell curve (calibrating it to expected returns and implied volaility based on option prices), then use standard formulas for lognormal distributions to calculate the probability of the price exceeding the strike price. So there are many assumptions involved, and in the end it's just a probability, so there's no way to know if it's right or wrong - either the stock will cross the strike or it won't." Investopedia has a good definition. Stock dividends are similar to cash dividends; however, instead of cash, a company pays out stock. Stock splits occur when a company perceives that its stock price may be too high. Stock splits are usually done to increase the liquidity of the stock (more shares outstanding) and to make it more affordable for investors to buy regular lots (a regular lot = 100 shares). Adjustments can be for splits as well as for dividends.  From Investopedia.com: Historical prices stored on some public websites, such as Yahoo!   Finance, also adjust the past prices of the stock downward by the   dividend amount. Thus, that could also be a possible factor in looking at the old prices. You haven't seen one because you haven't looked for one properly. You can set a google alert for stock split and get information about major issues splitting their stocks quite regularly, as well as a daily dose of recommendations from people without a say in the matter for big companies to split their stock. Stock splits are announced in advance by company management. Within the U.K., Third Party Resellers establish warehouses in the UK, but orders are placed overseas, and Amazon is not required to collect Value Added Tax on behalf of allegedly foreign owned resellers which rely on Amazon to sell items.  Amazon also evades the payment of tax by routing all sales through Luxembourg which, thanks to Jean Claude Juncker of the EU when Prime Minister of Luxembourg negotiated a generous tax sweetheart deal for multi national corporations (incl Amazon) to establish their base in Luxembourg.