Does longterm investment in index funds still make sense in a reality of massive algotrading?
What the automation mostly does is make short-term trading that much more difficult. Day trading is a zero-sum game, so if they win more, everyone else wins less.  Long term trading (years to decades) is a positive-sum game; the market as a whole tends to move upward for fairly obvious reasons (at its basis it's still investing, which in turn is based on lending, and as long as folks make fairly rational decisions about how much return they demand for their investment and the companies are mostly producing profits there will be a share of the profit coming back to the investors as dividends or increased share value or both. Day-to-day churn in individual stocks gets averaged out by diversification and time, and by the assumption that if you've waited that long you can wait a bit longer if necessary for jitters to settle out. Time periods between those will partake of some mix of the two. There is a difference between trading which is short term focussed and investing which is longterm focussed. On the long term what drives stock prices is still the overall economy and the performance of the underlying business aspects. I do not think that any trading algorithms will change this. These are more concerned with short term profits regardless of the underlying business economics. Therefore I think that longterm investing using index funds is still a viable strategy for most private investors. Why wouldn't you expect a long-term profit?  Say you buy 100 shares of company X, selling for$1/share today.  You hold it for 20 years, after which it's worth $10/share (in inflation-adjusted dollars).  So you've made a profit, only making two trades (buy & sell).  What the algorithmic traders have done with short-term trades during those 20 years is irrelevant to you. Now expand the idea.  You want some diversification, so instead of one stock, you buy a bit of all the stocks on whatever index interests you, and you just hold them for the same 20 years.  How has what the short-term traders done in the intervening time affected you?
"One approach is to invest in ""allocation"" mutual funds that use various methods to vary their asset allocation. Some examples (these are not recommendations; just to show you what I am talking about): A good way to identify a useful allocation fund is to look at the ""R-squared"" (correlation) with indexes on Morningstar. If the allocation fund has a 90-plus R-squared with any index, it probably isn't doing a lot. If it's relatively uncorrelated, then the manager is not index-hugging, but is making decisions to give you different risks from the index. If you put 10% of your portfolio in a fund that varies allocation to stocks from 25% to 75%, then your allocation to stocks created by that 10% would be between 2.5% to 7.5% depending on the views of the fund manager. You can use that type of calculation to invest enough in allocation funds to allow your overall allocation to vary within a desired range, and then you could put the rest of your money in index funds or whatever you normally use. You can think of this as diversifying across investment discipline in addition to across asset class. Another approach is to simply rely on your already balanced portfolio and enjoy any downturns in stocks as an opportunity to rebalance and buy some stocks at a lower price. Then enjoy any run-up as an opportunity to rebalance and sell some stocks at a high price.  The difficulty of course is going through with the rebalance. This is one advantage of all-in-one funds (target date, ""lifecycle,"" balanced, they have many names), they will always go through with the rebalance for you - and you can't ""see"" each bucket in order to get stressed about it. i.e. it's important to think of your portfolio as a whole, not look at the loss in the stocks portion. An all-in-one fund keeps you from seeing the stocks-by-themselves loss number, which is a good way to trick yourself into behaving sensibly. If you want to rebalance ""more aggressively"" then look at value averaging (search for ""value averaging"" on this site for example). A questionable approach is flat-out market-timing, where you try to get out and back in at the right times; a variation on this would be to buy put options at certain times; the problem is that it's just too hard. I think it makes more sense to buy an allocation fund that does this for you. If you do market time, you want to go in and out gradually, and value averaging is one way to do that." "You cannot actually buy an index in the true sense of the word.  An index is created and maintained by a company like Standard and Poor's who licenses the use of the index to firms like Vanguard.  The S&P 500 is an example of an index.  The S&P 500 ""index includes 500 leading companies"", many finical companies sell products which track to this index.  The two most popular products which track to indexes are Mutual Funds (as called Index Funds and Index Mutual Funds) and Exchange Traded Funds (as called ETFs).  Each Index Mutual Fund or ETF has an index which it tracks against, meaning they hold securities which make up a sample of the index (some indexes like bond indexes are very hard to hold everything that makes them up). Looking at the Vanguard S&P 500 Index Mutual Fund (ticker VFINX) we see that it tracks against the S&P 500 index.  Looking at its holdings we see the 500-ish stocks that it holds along with a small amount of bonds and cash to handle cash flow for people buying and sell shares.  If we look at the Vanguard S&P 500 ETF (ticker VOO) we see that it also tracks against the S&P 500 index.  Looking at its holdings we see they are very similar to the similar Index Mutual Fund. Other companies like T. Rowe Price have similar offering.  Look at the T. Rowe Price Equity Index 500 Fund (ticker PREIX) its holdings in stocks are the same as the similar Vanguard fund and like the Vanguard fund it also holds a small amount of bonds and cash to handle cash flow. The only real difference between different products which track against the same index is in the expense ratio (fees for managing the fund) and in the small differences in the execution of the funds.  For the most part execution of the funds do not really matter to most people (it has a very small effect), what matters is the expense (the fees paid to own the fund).  If we just compare the expense ratio of the Vanguard and T. Rowe Price funds we see (as of 27 Feb 2016) Vanguard has an expense ratio of 0.17% for it Index Mutual Fund and 0.05% for its ETF, while T. Rowe Price has an expense ratio of 0.27%.  These are just the fees for the funds themselves, there are also account maintenance fees (which normally go down as the amount of money you have invested at a firm go up) and in the case of ETFs execution cost (cost to trade the shares along with the difference between the bid and ask on the shares). If you are just starting out I would say going with the Index Mutual Fund would easier and most likely would cost less over-all if you are buying a small amount of shares every month.  When choosing a company look at the expense ratio on the funds and the account maintenance fees (along with the account minimals).  Vanguard is well known for having low fees and they in fact were the first to offer Index Mutual Funds. For more info on the S&P 500 index see also this Investopedia entry on the S&P 500 index. Do not worry if this is all a bit confusing it is to most people (myself included) at first." The S&P500 is an index, not an investment by itself.  The index lists a large number of stocks, and the value of the index is the price of all the stocks added together. If you want to make an investment that tracks the S&P500, you could buy some shares of each stock in the index, in the same proportions as the index.  This, however, is impractical for just about everyone. Index mutual funds provide an easy way to make this investment.  SPY is an ETF (exchange-traded mutual fund) that does the same thing. An index CFD (contract for difference) is not the same as an index mutual fund.  There are a number of differences between investing in a security fund and investing in a CFD, and CFDs are not available everywhere. "One alternative to bogleheadism is the permanent portfolio concept (do NOT buy the mutual fund behind this idea as you can easily obtain access to a low cost money market fund, stock index fund, and bond fund and significantly reduce the overall cost).  It doesn't have the huge booms that stock plans do, but it also doesn't have the crushing blows either.  One thing some advisers mention is success is more about what you can stick to than what ""traditionally"" makes sense, as you may not be able to stick to what traditionally makes sense (all people differ). This is an excellent pro and con critique of the permanent portfolio (read the whole thing) that does highlight some of the concerns with it, especially the big one: how well will it do in a world of high interest rates?  Assuming we ever see a world of high interest rates, it may not provide a great return. The authors make the assumption that interest rates will be rising in the future, thus the permanent portfolio is riskier than a traditional 60/40.  As we're seeing in Europe, I think we're headed for a world of negative interest rates - something in the past most advisers have thought was very unlikely.  I don't know if we'll see interest rates above 6% in my lifetime and if I live as long as my father, that's a good 60+ years ahead. (I realize people will think this is crazy to write, but consider that people are willing to pay governments money to hold their cash - that's how crazy our world is and I don't see this changing.)" If you have your long positions established and are investing responsibly (assuming you know the risks and can accept them), the next step IMO is typically learning hedging - using options or option strategies to solidify positions. Collars (zero cost) and put options are a good place to start your education and they can be put to use to both speculate (what you are effectively doing with short-position trading) or long-term oriented edging. Day trading equites can be lucrative but it is a difficult game to play - learning options (while more complex on speculation) can provide opportunities to solidify positions. Options trading is difficult grounds. I just think the payoff long term to knowing options is much greater than day-trading tactics (because of versatility) Those are valid, but I think you will see banks move into fintech, as they already have, and they are also moving into blockchain. One thing that banks have, is money, and that allows them to move into new spaces in the economy even if they are late to the party. When you have institutions that have been around for more than a century, they don’t just go away.   I think you start to see trading revenue comeback, eventually. The passive versus active investing is a cycle. As more and more people jump into passive investments, it will inevitably change the market because suddenly everything becomes more correlated. Once there is enough volatility to scare people out of their passive investments, then the indices are going to fall. Then you’ll start seeing how active investing is better and people start to move back. Passive investing is good when everything is up, but on the downside active investing (if you have the right managers) will outperform. Once this occurs, you will start to see more volatility in the markets again, and a return to active management, until inevitably people start to move back to passive again. "I think this gets at why some of us are becoming concerned about the volume (or more importantly the portion) of HFT in capital markets these days. You have algos trading based on ""technical trends"" which are increasingly just the behavior of other algos. Rinse and repeat. At a certain point it just becomes a feedback loop.  Now, I agree that there's no reason to be scared of HFT simply because its new or fast, which is what I think threatens a lot of people. But the problem is that the economic and social utility of markets arises from their being information aggregation engines. If it gets to the point where most of the price action is driven by algos which are trading solely based on a few minutes of technical data, no new information is being contributed to the price discovery process.   Now, it may be that a certain amount of ""meta-information"" can be discovered from pattern analysis of short term technical history. But it seems to me this information is more limited in both quality and quantity compared to the information inputs of thoughtful humans acting on a reasoned analysis of economic and other world events." I guess I wasn't clear. I want to modestly leverage (3-4x) my portfolio using options. I believe long deep-in-the-money calls would be the best way to do this? (Let me know if not.)  It's important to me that the covariance matrix from the equity portfolio scales up but doesn't fundamentally change. (I liken it to systemic change as opposed to idiosyncratic change.)   This is what I was thinking:  * For the same expiry date, find each positions lowest lambda. * Match all option to the the highest of the lowest lambda. * Adjust number of contracts to compensate for higher leverage.  I don't think this will work because if I matched the lowest lambda of options on bond etfs to my equity options they would be out-of-the-money.  By the way, thanks for your time.