Where can I find historical P/E ratios for companies?
"The mathematics site, WolframAlpha, provides such data. Here is a link to historic p/e data for Apple. You can chart other companies simply by typing ""p/e code"" into the search box.  For example, ""p/e XOM"" will give you historic p/e data for Exxon. A drop-down list box allows you to select a reporting period : 2 years, 5 years, 10 years, all data.  Below the chart you can read the minimum, maximum, and average p/e for the reporting period in addition to the dates on which the minimum and maximum were applicable."
But they beat most revenue estimates... should be a heavy down day tomorrow, even though the stock is already massively oversold, especially when compared to industry peers and average P/E ratios of tech companies.  Last 12 months of earnings: $44.16 "It's been said before, but to repeat succinctly, a company's current share price is no more or less than what ""the market"" thinks that share is worth, as measured by the price at which the shares are being bought and sold. As such, a lot of things can affect that price, some of them material, others ethereal. A common reason to own stock is to share the profits of the company; by owning 1 share out of 1 million shares outstanding, you are entitled to 1/1000000 of that company's quarterly profits (if any). These are paid out as dividends. Two key measurements are based on these dividend payments; the first is ""earnings per share"", which is the company's stated quarterly profits, divided by outstanding shares, with the second being the ""price-earnings ratio"" which is the current price of the stock divided by its EPS. Your expected ""yield"" on this stock is more or less the inverse of this number; if a company has a P/E ratio of 20, then all things being equal, if you invest $100 in this stock you can expect a return of $5, or 5% (1/20). As such, changes in the expected earnings per share can cause the share price to rise or fall to maintain a P/E ratio that the pool of buyers are willing to tolerate. News that a company might miss its profit expectations, due to a decrease in consumer demand, an increase in raw materials costs, labor, financing, or any of a multitude of things that industry analysts watch, can cause the stock price to drop sharply as people look for better investments with higher yields. However, a large P/E ratio is not necessarily a bad thing, especially for a large stable company. That stability means the company is better able to weather economic problems, and thus it is a lower risk. Now, not all companies issue dividends. Apple is probably the most well-known example. The company simply retains all its earnings to reinvest in itself. This is typically the strategy of a smaller start-up; whether they're making good money or not, they typically want to keep what they make so they can keep growing, and the shareholders are usually fine with that. Why? Well, because there's more than one way to value a company, and more than one way to look at a stock. Owning one share of a stock can be seen quite literally as owning a share of that company. The share can then be valued as a fraction of the company's total assets.  Sounds simple, but it isn't, because not every asset the company owns has a line in the financial statements. A company's brand name, for instance, has no tangible value, and yet it is probably the most valuable single thing Apple owns. Similarly, intellectual property doesn't have a ""book value"" on a company's balance sheet, but again, these are huge contributors to the success and profitability of a company like Apple; the company is viewed as a center of innovation, and if it were not doing any innovating, it would very quickly be seen as a middleman for some other company's ideas and products. A company can't sustain that position for long even if it's raking in the money in the meantime. Overall, the value of a company is generally a combination of these two things; by owning a portion of stock, you own a piece of the company's assets, and also claim a piece of their profits. A large company with a lot of material assets and very little debt can be highly valued based solely on the sum of its parts, even if profits are lagging. Conversely, a company more or less operating out of a storage unit can have a patent on the cure for cancer, and be shoveling money into their coffers with bulldozers." Try to find the P/E ratio of the Company and then Multiply it with last E.P.S, this calculation gives the Fundamental Value of the share, anything higher than this Value is not acceptable and Vice versa. &gt;Well, reserve requirements concern, as the name suggests, the reserves, e.g. a position on the balance sheet.  Yes, the book value of equity is not affected. However, when the market value experiences a steep decline, you find those that hold deposits begin moving them out of the bank. Investment fear and business fear tend to move together with financial institutions. That directly impacts the reserve requirements.  &gt;but sharp price drops in fact can help you to raise equity, simply because your ratios improved (P/E, P/B, in fact any ratio that includes the price part) and the stock became cheaper  Not when there is bankruptcy or solvency issues that become present. Obviously an investor wants to buy low and sell high, but if there is a substantial risk of bankruptcy, the common stockholder will demand a premium unattainable by most non-growth firms (i.e. biotech, tech, etc.).  That is the issue with France. Liquidity issues stem from systemic risk, but those French banks also possess significant firm risk due to their exposure to sovereign debt. Once those banks mark all of their holdings to market, they will realize substantial losses. BNP recently recorded a nearly $1B write-down. There are multiple places where you can see this.  Company house website On any financial news website, if you have access e.g. TESCO on FT On any 3rd party website which supply information on companies e.g. TESCO on Companycheck An observation though, FT lists down more shareholders for me than Companycheck as I pay for FT. You can use Google Finance Stock Screener for screening US stocks. Apparently it doesn't have the specific criterion (Last Price % diff from 52 week low) you are (were!) looking for.  I believe using its api you can get it, although it won't exactly be a very direct solution. P/E can use various estimates in its calculation as one could speculate about future P/E rations and thus could determine a future valuation if one is prepared to say that the P/E should be X for a company. Course it is worth noting that if a company isn't generating positive earnings this can be a less than useful tool, e.g. Amazon in the 1990s lost money every quarter and thus would have had a N/A for a P/E. PEG would use P/E and earnings growth as a way to see if a stock is overvalued based on projected growth. If a company has a high P/E but has a high earnings growth rate then that may prove to be worth it. By using the growth rate, one can get a better idea of the context to that figure. Another way to gain context on P/E would be to look at industry averages that would often be found on Yahoo! Finance and other sites. "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."