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What is the best asset allocation for a retirement portfolio, and why?
Aggressiveness in a retirement portfolio is usually a function of your age and your risk tolerance. Your portfolio is usually a mix of the following asset classes: You can break down these asset classes further, but each one is a topic unto itself. If you are young, you want to invest in things that have a higher return, but are more volatile, because market fluctuations (like the current financial meltdown) will be long gone before you reach retirement age.  This means that at a younger age, you should be investing more in stocks and foreign/developing countries. If you are older, you need to be into more conservative investments (bonds, money market, etc).  If you were in your 50s-60s and still heavily invested in stock, something like the current financial crisis could have ruined your retirement plans.  (A lot of baby boomers learned this the hard way.) For most of your life, you will probably be somewhere in between these two.  Start aggressive, and gradually get more conservative as you get older.  You will probably need to re-check your asset allocation once every 5 years or so. As for how much of each investment class, there are no hard and fast rules.  The idea is to maximize return while accepting a certain amount of risk.  There are two big unknowns in there: (1) how much return do you expect from the various investments, and (2) how much risk are you willing to accept.  #1 is a big guess, and #2 is personal opinion. A general portfolio guideline is "100 minus your age".  This means if you are 20, you should have 80% of your retirement portfolio in stocks.  If you are 60, your retirement portfolio should be 40% stock.  Over the years, the "100" number has varied.  Some financial advisor types have suggested "150" or "200".  Unfortunately, that's why a lot of baby boomers can't retire now. Above all, re-balance your portfolio regularly.  At least once a year, perhaps quarterly if the market is going wild.  Make sure you are still in-line with your desired asset allocation.  If the stock market tanks and you are under-invested in stocks, buy more stock, selling off other funds if necessary.  (I've read interviews with fund managers who say failure to rebalance in a down stock market is one of the big mistakes people make when managing a retirement portfolio.) As for specific mutual fund suggestions, I'm not going to do that, because it depends on what your 401k or IRA has available as investment options.  I do suggest that your focus on selecting a "passive" index fund, not an actively managed fund with a high expense ratio. Personally, I like "total market" funds to give you the broadest allocation of small and big companies.  (This makes your question about large/small cap stocks moot.)  The next best choice would be an S&P 500 index fund. You should also be able to find a low-cost Bond Index Fund that will give you a healthy mix of different bond types. However, you need to look at expense ratios to make an informed decision.  A better-performing fund is pointless if you lose it all to fees! Also, watch out for overlap between your fund choices.  Investing in both a Total Market fund, and an S&P 500 fund undermines the idea of a diversified portfolio. An aggressive portfolio usually includes some Foreign/Developing Nation investments.  There aren't many index fund options here, so you may have to go with an actively-managed fund (with a much higher expense ratio).  However, this kind of investment can be worth it to take advantage of the economic growth in places like China. http://www.getrichslowly.org/blog/2009/04/27/how-to-create-your-own-target-date-mutual-fund/