How can IV give an indication of the markets opinion about a stock when there's no such thing as IV for a stock?
Since near-term at-the-money (ATM) options are generally the most liquid, the listed implied vol for a stock is usually pretty close to the nearest ATM volatility, but there's not a set convention that I'm aware of.  Also note that for most stocks, vol skew (the difference in vol between away-from-the-money and at-the-money options) is relatively small,  correct me if I'm wrong, IV is the markets assessment that the stock is about 70% likely (1 Standard Deviation) to move (in either direction) by that percent over the next year. Not exactly.  It's an annualized standard deviation of the anticipated movements over the time period of the option that it's implied from.  Implied vol for near-term options can be higher or lower than longer-term options, depending on if the market believes that there will be more uncertainty in the short-term.  Also, it's the bounds of the expected movement in that time period. so if a stock is at $100 with an implied vol of 30% for 1-year term options, then the market thinks that the stock will be somewhere between $70 and $130 after 1 year.  If you look at the implied vol for a 6-month term option, half of that vol is the range of expected movement in 6 months.
"If you are looking for numerical metrics I think the following are popular: Price/Earnings (P/E) - You mentioned this very popular one in your question.  There are different P/E ratios - forward (essentially an estimate of future earnings by management), trailing, etc..  I think of the P/E as a quick way to grade a company's income statement (i.e: How much does the stock cost verusus the amount of earnings being generated on a per share basis?). Some caution must be taken when looking at the P/E ratio.  Earnings can be ""massaged"" by the company.  Revenue can be moved between quarters, assets can be depreciated at different rates, residual value of assets can be adjusted, etc..  Knowing this, the P/E ratio alone doesn't help me determine whether or not a stock is cheap. In general, I think an affordable stock is one whose P/E is under 15. Price/Book - I look at the Price/Book as a quick way to grade a company's balance sheet.  The book value of a company is the amount of cash that would be left if everything the company owned was sold and all debts paid (i.e. the company's net worth).  The cash is then divided amoung the outstanding shares and the Price/Book can be computed.  If a company had a price/book under 1.0 then theoretically you could purchase the stock, the company could be liquidated, and you would end up with more money then what you paid for the stock. This ratio attempts to answer: ""How much does the stock cost based on the net worth of the company?"" Again, this ratio can be ""massaged"" by the company.  Asset values have to be estimated based on current market values (think about trying to determine how much a company's building is worth) unless, of course, mark-to-market is suspended.  This involves some estimating.  Again, I don't use this value alone in determing whether or not a stock is cheap. I consider a price/book value under 10 a good number.   Cash - I look at growth in the cash balance of a company as a way to grade a company's cash flow statement.  Is the cash account growing or not? As they say, ""Cash is King"".  This is one measurement that can not be ""massaged"" which is why I like it.  The P/E and Price/Book can be ""tuned"" but in the end the company cannot hide a shrinking cash balance. Return Ratios - Return on Equity is a measure of the amount of earnings being generated for a given amount of equity (ROE = earnings/(assets - liabilities)).  This attempts to measure how effective the company is at generating earnings with a given amount of equity.  There is also Return on Assets which measures earnings returns based on the company's assets. I tend to think an ROE over 15% is a good number. These measurements rely on a company accurately reporting its financial condition.  Remember, in the US companies are allowed to falsify accounting reports if approved by the government so be careful.  There are others who simply don't follow the rules and report whatever numbers they like without penalty. There are many others.  These are just a few of the more popular ones.  There are many other considerations to take into account as other posters have pointed out." "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)." In my original question, I  was wondering if there was a mathematical convention to help in deciding on whether an equity offering OR debt offering would be a better choice. I should have clarified better in the question, I used Vs. which may have made it unclear. My reaction to this is that your observation @D.W. is spot on correct: It sounds like long-term market timing: trying to do a better job than   the rest of the market at predicting, based upon a simple formula,   whether the market is over-priced or under-priced. I read the post by the founder of Valuation Informed Indexing, Rob Bennet. Glance at  the comments section. Rob clearly states that he doesn't even use his own strategy, and has not owned, nor traded, any stocks since 1996! As another commenter summarizes it, addressing Rob: This is 2011. You’ve been 100% out of stocks — including indexes —   since 1996? That’s 15 years of taking whatever the bond market, CDs or   TIPS will yield (often and currently less than 2%)... I’m curious how   you defend not following your own program even as you recommend it for   others? Rob basically says that stocks haven't shown the right signals for buying since 1996, so he's stuck with bonds, CD's and fixed-income instead. This is a VERY long-term horizon point of view (a bit of sarcasm edges in from me). Answering your more general question, what do I think of this particular Price/ Earnings based ratio as a way to signal asset allocation change i.e. Valuation Informed Investing? I don't like it much. There are those who would suggest that due to the Efficient Market Hypothesis, stocks are always fairly valued. Consider, if non-professional posters on SE (here) had a method that worked beyond random chance, everyone seeking such a method would soon know it. If everyone used that method, it would lose its advantage. In theory, this is how stocks' values remain rational.  That said, Williams %R is one such indicator. It can be seen in action on Yahoo finance -  In the end, I find such indicators far less useful than the news itself. BP oil spill - Did anyone believe that such a huge oil company wouldn't recover from that disaster? It recovered by nearly doubling from its bottom after that news. A chart of NFLX (Netflix) offers a similar news disaster, and recovery.  Both of these examples are not quantifiable, in my opinion, just gut reactions. A quick look at the company and answer to one question - Do I feel this company will recover? To be candid - in the 08/09 crash, I felt that way about Ford and GM. Ford returned 10X from the bottom, GM went through bankruptcy. That observation suggests another question, i.e. where is the line drawn between 'investing' and 'gambling'? My answer is that buying one stock hoping for its recovery is gambling. Being able to do this for 5-10 stocks, or one every few months, is investing. The indication is based on the average Buy-Hold-Sell rating of a group of fundamental analysts. The individual analysts provide a Buy, Hold or Sell recommendation based on where the current price of the stock is compared to the perceived value of the stock by the analyst.  Note that this perceived value is based on many assumptions by the analyst and their biased view of the stock. That is why different fundamental analysts provide different values and different recommendations on the same stock. So basically if the stock's price is below the analyst's perceived value it will be given a Buy recommendation, if the price is equal with the perceived value it will be given a Hold recommendation and if the price is more than the perceived value it will be given a Sell recommendation. As the others have said this information IMHO is useless. From every article I've encountered, the chicken and egg aspect suggests that IV is produced by looking at options pricing, and calculating the IV from that.  The implication is that whatever is known at that time is included in the price. And that when you see a particular option trade an unusual number of contracts at a given price, the implication is that someone thinks they know something that's not already priced in, i.e. that the current price is not accurate, they can profit on the future event. "VaR does not do what it is supposed to do which is give you a ""floor"" with confidence on your potential losses.  Even for portfolios with millions of instruments, it will not give you a metric that means anything.  The point im trying to convey is that VaR does not give any meaningful information as its horribly inaccurate and that we would be better off WITHOUT VaR." Historical volatility of a stock is going to be based on past performance, basically its current trend.  That can be useful, but really is no indication of how it will perform in the future.  Especially with a big swing in the market. Now if you're talking about implied volatility (IV) of an options contract, that's a little different.  IV is derived from an option’s price and shows what the market “implies” about the stock’s volatility in the future. Thus it is based on the actions of active traders and market makers.  So, it gives you a bit more insight into what's going on, but at times has less to do with fundamentals. I guess a good way to think of IV based on options contracts is as an educated opinion, of the market as a whole, with regards to how much that stock could likely move over a period of time (options expiration). Also note that IV represents the potential for a stock to move, but it does not forecast direction. I don't know of any studies off the top of my head, but I'm sure there have been plenty. For whatever reason, I don't believe they offer it.  Yahoo does.  A google for google finance VIX turns up people asking the question, but no quote on google. "A bit strange but okay.  The way I would think about this is again that you need to determine for what purpose you're computing this, in much the same way you would if you were to build out the model. The IPO valuation is not going to be relevant to the accretion/dilution analysis unless you're trying to determine whether the transaction was net accretive at exit. But that's a weird analysis to do. For longer holding periods like that you're more likely to look at IRR, not EPS. EPS is something investors look at over the short to medium term to get a sense of whether the company is making good acquisition decisions. And to do that short-to-medium term analysis, they look at earnings.   Damodaran would say this is a shitty way of looking at things and that you should probably be looking at some measure of ROIC instead, and I tend to agree, but I don't get paid to think like an investor, I get paid to sell shit to them (if only in indirect fashion). The short answer to your question is that no, you should not incorporate what you are calling liquidation value when determining accretion/dilution, but only because the market typically computes accretion/dilution on a 3-year basis tops. I've never put together a book or seen a press release in my admittedly short time in finance that says ""the transaction is estimated to be X% accretive within 4 years"" - that just seems like an absurd timeline.  Final point is just that from an accounting perspective, a gain on a sale of an asset is not going to get booked in either EBITDA or OCF, so just mechanically there's no way for the IPO value to flow into your accretion/dilution analysis there, even if you are looking at EBITDA/shares. You could figure the gain on sale into some kind of adjusted EBITDA/shares version of EPS, but this is neither something I've ever seen nor something that really makes sense in the context of using EPS as a standardized metric across the market. Typically we take OUT non-recurring shit in EPS, we don't add it in. Adding something like this in would be much more appropriate to measuring the success of an acquisition/investing vehicle like a private equity fund, not a standalone operating company that reports operational earnings in addition to cash flow from investing. And as I suggest above, that's an analysis for which the IRR metric is more ideally situated.  And just a semantic thing - we typically wouldn't call the exit value a ""liquidation value"". That term is usually reserved for dissolution of a corporate entity and selling off its physical or intangible assets in piecemeal fashion (i.e. not accounting for operational synergies across the business). IPO value is actually just going to be a measure of market value of equity." "would constantly fluctuate and provide an indication of how well the market is doing. The index is there to tell if you made profit or loss by investing in the market.  Using a pure total market cap will only tell you ""Did IPO activity exceed bankruptcy and privatization activity""." "Most likely because they don't know what they're talking about. They all have a belief without evidence that information set X is internalised into the price but information set Y is not. If there is some stock characteristic, call it y, that belongs to set Y, then that moves the gauge towards a ""buy"" recommendation. However, the issue is that no evidence has been used to determine the constituents of X and Y, or even whether Y exists in any non-trivial sense." Your understanding of the stock market is absolutely correct theoretically. However there is a lot more to it. A stock on a given day is effected by a lot of factors. These factors could really be anything. For example, if you are buying a stock in an agricultural company and there was no rainfall this year, there is a big chance that your stock will lose value. There is also a chance that a war breaks out tomorrow and due to all the government spending on the war, the economy collapses and effects the prices of stocks. Why does this happen? This happens because bad rainfall or war can get people to lose confidence in a stock market. On the other hand GDP growth and low unemployment rates can make people think positive and increase the demand in a stock driving the prices up. The main factor in the stock market is sentiment(How people perceive certain news). This causes a stock to rise or fall even before the event actually happens. (For example:- Weather pundits predicted good rainfall for next year. That news is already known to people, so if the weather pundit was correct, it might not drive the prices up. However, if the rainfall was way better than people expected it to be it would drive the price up and vice versa.   These are just examples at a basic level. There are a lot of other factors which determine the price of the stock. The best way to look at it(In my personal opinion) is the way Warren Buffet puts it, i.e. look at the stock as a business and see the potential growth over a long period of time.  There will be unexpected events, but in the long run, the business must be profitable. There are various ways to value a company such as Price to earnings ratios, PEG ratios, discounted cash flows and you can also create your own. See what works best for you and record your success/failure ratio before you actually put money in.  Good Luck, I'm not exactly sure, but it may be due to liquidity preference.  SPY has a much higher volume (30d average of roughly 70m vs. 3.3m, 1.9m for IVV, VOO respectively), and similarly has a narrow bid ask spread of about 0.01 compared to 0.02 for the other two.  I could be wrong, but I'm going to leave this post up and look in to it later, I'm curious too. The difference is very consistent though, so it may be something in their methodology.