The stock exchanges also maintain all company news, announcements, and financial reporting, which can be usually accessed on their official websites. A stock exchange also supports various other corporate-level, transaction-related activities. For instance, profitable companies may reward investors by paying dividends which usually comes from a part of the company’s earnings. The exchange maintains all such information and may support its processing to a certain extent. (For related reading, see "How Does the Stock Market Work?")

To make comparisons between companies, sectors and markets a little easier, there are a number of mathematical models used. The most common and often the most helpful is the P/E ratio. The Price to Earnings ratio takes the share price and is divided by the earnings per share. It is possible to calculate this using past earnings, projected future earnings and with all sorts of moving averages ;-) Therefore, this is one number that it is vital for any investor to know and understand.

This survey was conducted online within the United States by The Harris Poll on behalf of NerdWallet from June 14-18, 2018, among 2,024 U.S. adults ages 18 and older, among whom 787 were invested in in the stock market during at least one of the past five financial downturns. This online survey is not based on a probability sample and therefore no estimate of theoretical sampling error can be calculated. For complete survey methodology, including weighting variables and subgroup sample sizes, please contact Megan Katz at [email protected]
It’s likely some of these Americans might rethink pulling their money if they knew how quickly a portfolio can rebound from the bottom: The market took just 13 months to recover its losses after the most recent major sell-off in 2015. Even the Great Recession — a devastating downturn of historic proportions — posted a complete market recovery in just over five years. The S&P 500 then posted a compound annual growth rate of 16% from 2013 to 2017 (including dividends).

When you buy a stock, you should have a good reason for doing so and an expectation of what the price will do if the reason is valid. At the same time, you should establish the point at which you will liquidate your holdings, especially if your reason is proven invalid or if the stock doesn’t react as expected when your expectation has been met. In other words, have an exit strategy before you buy the security and execute that strategy unemotionally.
Why I’m buying: Spell out what you find attractive about the company and the opportunity you see for the future. What are your expectations? What metrics matter most and what milestones will you use to judge the company’s progress? Catalog the potential pitfalls and mark which ones would be game-changers and which would be signs of a temporary setback.