Investing: P/E Ratio basic question
The idea here is to get an idea of how to value each business and thus normalize how highly prized is each dollar that a company makes.  While some companies may make millions and others make billions, how does one put these in proper context?  One way is to consider a dollar in earnings for the company.  How does a dollar in earnings for Google compare to a dollar for Coca-cola for example?  Some companies may be valued much higher than others and this is a way to see that as share price alone can be rather misleading since some companies can have millions of shares outstanding and split the shares to keep the share price in a certain range. Thus the idea isn't that an investor is paying for a dollar of earnings but rather how is that perceived as some companies may not have earnings and yet still be traded as start-ups and other companies may be running at a loss and thus the P/E isn't even meaningful in this case. Assuming everything but the P/E is the same, the lower P/E would represent a greater value in a sense, yes.  However, earnings growth rate can account for higher P/Es for some companies as if a company is expected to grow at 40% for a few years it may have a higher P/E than a company growing earnings at 5% for example. Let's take a step back. My fictional company 'A' is a solid, old, established company. It's in consumer staples, so people buy the products in good times and bad. It has a dividend of $1/yr. Only knowing this, you have to decide how much you would be willing to pay for one share.  You might decide that $20 is fair. Why? Because that's a 5% return on your money, 1/20 = 5%, and given the current rates, you're happy for a 5% dividend. But this company doesn't give out all its earnings as a dividend. It really earns $1.50, so the P/E you are willing to pay is 20/1.5 or 13.3.  Many companies offer no dividend, but of course they still might have earnings, and the P/E is one metric that used to judge whether one wishes to buy a stock.  A high P/E implies the buyers think the stock will have future growth, and they are wiling to pay more today to hold it. A low P/E might be a sign the company is solid, but not growing, if such a thing is possible. While on the surface it might not make sense to pay more than one dollar to get just one dollar back, the key thing is that a good company's earnings are recurring each year. So, you wouldn't just be paying for the $1 dollar of earnings per share this year, but for the entire future stream of earnings per share, every year, in perpetuity -- and the earnings may grow over time too (if it remains a good company.) Your stock is a claim on a portion of the company's future. The brighter and/or more certain that future, the more investors are willing to pay for each recurring dollar of earnings. And the P/E ratio tells you, in effect, how many years it might take for your investment to earn back what you paid – assuming earnings remain the same. But you would hope the earnings would grow, too. When a company's earnings are widely expected to grow, the P/E for the stock is often higher than average. Bear in mind you don't actually receive the company's earnings, since management often decides to reinvest all or a portion of it to grow the company. Yet, many companies do pay a portion of earnings out as dividends. Dividends are money in your pocket each year.
&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. "Below I will try to explain two most common Binomial Option Pricing Models (BOPM) used. First of all, BOPM splits time to expiry into N equal sub-periods and assumes that in each period the underlying security price may rise or fall by a known proportion, so the value of an option in any sub-period is a function of its possible values in the following sub period. Therefore the current value of an option is found by working backwards from expiry date through sub-periods to current time. There is not enough information in the question from your textbook so we may assume that what you are asked to do is to find a value of a call option using just a Single Period BOPM. Here are two ways of doing this: First of all let's summarize your information: Current Share Price (Vs) = $70 Strike or exercise price (X) = $60 Risk-free rate (r) = 5.5% or 0.055 Time to maturity (t) = 12 months Downward movement in share price for the period (d) = $65 / $70 = 0.928571429 Upward movement in share price for the period (u) = 1/d = 1/0.928571429 = 1.076923077 ""u"" can be translated to $ multiplying by Vs => 1.076923077 * $70 = $75.38 which is the maximum probable share price in 12 months time. If you need more clarification here - the minimum and maximum future share prices are calculated from stocks past volatility which is a measure of risk. But because your textbook question does not seem to be asking this - you probably don't have to bother too much about it yet. Intrinsic Value: Just in case someone reading this is unclear - the Value of an option on maturity is the difference between the exercise (strike) price and the value of a share at the time of the option maturity. This is also called an intrinsic value.  Note that American Option can be exercised prior to it's maturity in this case the intrinsic value it simply the diference between strike price and the underlying share price at the time of an exercise. But the Value of an option at period 0 (also called option price) is a price you would normally pay in order to buy it. So, say, with a strike of $60 and Share Price of $70 the intrinsic value is $10, whereas if Share Price was $50 the intrinsic value would be $0. The option price or the value of a call option in both cases would be fixed.  So we also need to find intrinsic option values when price falls to the lowest probable and rises to the maximum probable (Vcd and Vcu respectively) (Vcd) = $65-$60 = $5 (remember if Strike was $70 then Vcd would be $0 because nobody would exercise an option that is out of the money) (Vcu) = $75.38-$60 = $15.38 1. Setting up a hedge ratio:  h = Vs*(u-d)/(Vcu-Vcd) h = 70*(1.076923077-0.928571429)/(15.38-5) = 1 That means we have to write (sell) 1 option for each share purchased in order to hedge the risks. You can make a simple calculation to check this, but I'm not going to go into too much detail here as the equestion is not about hedging. Because this position is risk-free in equilibrium it should pay a risk-free rate (5.5%). Then, the formula to price an option (Vc) using the hedging approach is: (Vs-hVc)(e^(rt))=(Vsu-hVcu) Where (Vc) is the value of the call option, (h) is the hedge ratio, (Vs) - Current Share Price, (Vsu) - highest probable share price, (r) - risk-free rate, (t) - time in years, (Vcu) - value of a call option on maturity at the highest probable share price. Therefore solving for (Vc): (70-1*Vc)(e^(0.055*(12/12))) = (75.38-1*15.38) => (70-Vc)*1.056540615 = 60 => 70-Vc = 60/1.056540615 => Vc = 70 - (60/1.056540615)  Which is similar to the formula given in your textbook, so I must assume that using 1+r would be simply a very close approximation of the formula above. Then it is easy to find that Vc = 13.2108911402 ~ $13.21 2. Risk-neutral valuation: Another way to calculate (Vc) is using a risk-neutral approach. We first introduce a variable (p) which is a risk-neutral probability of an increase in share price. p = (e^(r*t)-d)/(u-d) so in your case: p = (1.056540615-0.928571429)/(1.076923077-0.928571429) = 0.862607107 Therefore using (p) the (Vc) would be equal: Vc = [pVcu+(1-p)Vcd]/(e^(rt)) => Vc = [(0.862607107*15.38)+(0.137392893*5)]/1.056540615 => Vc = 13.2071229185 ~ $13.21 As you can see it is very close to the hedging approach. I hope this answers your questions. Also bear in mind that there is much more to the option pricing than this. The most important topics to cover are: Multi-period BOPM Accounting for Dividends Black-Scholes-Merton Option Pricing Model" When fundamentals such as P/E make a stock look overpriced, analysts often point to other metrics. The PEG ratio, for example, can be applied to cast growth companies in a better light.  Fundamental analysis is highly subjective. For further discussion on the pitfalls of fundamentals, I suggest A Random Walk Down Wall Street by Burton Malkiel. "If you look at the biotech breakdown, you'll find a lot of NAs when it comes to P/E since there are many young biotech companies that have yet to make a profit.  Thus, there may be something to be said for how is the entire industry stat computed. Biotechnology can include pharmaceutical companies that can have big profits due to patents on drugs. As an example, look at Shire PLC which has a P/E of 1243 which is pretty high with a Market Capitalization of over a billion dollars, so this isn't a small company.  I wonder what dot-com companies would have looked like in 1998/1999 that could well be similar as some industries will have bubbles you do realize, right? The reason for pointing out the Market Capitalization is that this a way to measure the size of a company, as this is merely the sum of all the stock of the company.  There could be small companies that have low market capitalizations that could have high P/Es as they are relatively young and could be believed to have enough hype that there is a great deal of confidence in the stock.  For example, Amazon.com was public for years before turning a profit.  In being without profits, there is no P/E and thus it is worth understanding the limitations of a P/E as the computation just takes the previous year's earnings for a company divided by the current stock price.  If the expected growth rate is high enough this can be a way to justify a high P/E for a stock.  The question you asked about an industry having this is the derivation from a set of stocks.  If most of the stocks are high enough, then whatever mean or median one wants to use as the ""industry average"" will come from that." P/E ratio is useful but limited as others have said. Another problem is that it doesn't show leverage. Two companies in the same industry could have the same P/E but be differently leveraged. In that case I would buy the company with more equity and less debt as it should be a less risky investment. To compare companies and take leverage/debt into account you could use the EV/EBIT ratio instead. Its slightly more complicated to calculate and isn't presented by as many data sources though. Enterprise Value (EV) can be said to represent the value of the company if someone would buy it today and then pay off all its (interest bearing) debt. EV is essentially calculated like this: (Market Capitalization plus cash & cash equivalents)  minus interest-bearing debt.  This is then divided by EBIT (Earnings before interest and tax) to get the ratio. One drawback of this ratio though is that it can't be used for financials since their balance sheet pretty much consists of debt and the Enterprise Value therefore doesn't tell us very much. Also, like the P/E ratio it is dependent on fresh numbers. A balance sheet is just a glimpse of the companys financial situation on ONE DAY, and this could (and probably will, although not drastically for bigger companies) change to the next day. Your original example is a little confusing because just shorting for 1k and buying for 1k is 100% leveraged or an infinitive leverage ratio. (and not allowed) Brokerage houses would require you to invest some capital in the trade.  One example might be requiring you to hold $100 in the brokerage.  This is where the 10:1 ratio comes from. (1000/10) Thus a return of 4.5% on the 1000k bond and no movement on the short position would net you $45 and voila a 45% return on your $100 investment. A 40 to 1 leverage ratio would mean that you would only have to invest $25 to make this trade.  Something that no individual investor are allowed to do, but for some reason some financial firms have been able to. "Thanks.  This is super simplified as I said.  It gets much deeper when you start looking at costs of capital, country risk premiums (for projects in emerging markets), ""risk free rate of return"" (putting cash in guaranteed returns such as a us treasury note), mutually exclusive projects, etc.  But the basic concept is... what is the minimum required return on a project to justify choosing to pursue it.  If you borrow money via loan at 10%, your required rate of return on whatever project you invest it in has to be at least that 10%.  Otherwise you're better off just not doing anything." P/E = price per earnings. low P/E (P/E < 4) means stock is undervalued.