What traditionally happens to bonds when the stock market crashes?
The short answer is if you own a representative index of global bonds (say AGG) and global stocks (say ACWI) the bonds will generally only suffer minimally in even the medium large market crashes you describe.  However, there are some caveats. Not all bonds will tend to react the same way.  Bonds that are considered higher-yield (say BBB rated and below) tend to drop significantly in stock market crashes though not as much as stock markets themselves.  Emerging market bonds can drop even more as weaker foreign currencies can drop in global crashes as well. Also, if a local market crash is caused by rampant inflation as in the US during the 70s-80s, bonds can crash at the same time as markets.  There hasn't been a global crash caused by inflation after countries left the gold standard, but that doesn't mean it can't happen. Still, I don't mean to scare you away from adding bond exposure to a stock portfolio as bonds tend to have low correlations with stocks and significant returns.  Just be aware that these correlations can change over time (sometimes quickly) and depend on which stocks/bonds you invest in. It depends.  Very generally when yields go up stocks go down and when yields go down stocks go up (as has been happening lately). If we look at the yield of the 10 year bond it reflects future expectations for interest rates.  If the rate today is very low but expectations are that the short term rates will go up that would be reflected in a higher yield simply because no one would buy the longer term bond if they could simply wait out and get a better return on shoter term investments.  If expectations are that the rate is going down you get what's called an inverted yield curve.  The inverted yield curve is usually a sign of economic trouble ahead.  Yields are also influenced by inflation expectations as @rhaskett is alluding in his answer. So.  If the stock market crashes because the economy is doing poorly and if interest rates are relatively high then people would expect the rates to go down and therefore bonds will go up! However, if there's rampant inflation and the rates are going up we can expect stocks and bonds to move in opposite directions.  Another interpretation of that is that one would expect stock prices to track inflation pretty well because company revenue is going to go up with inflation.  If we're just talking about a bump in the road correction in a healthy economy I wouldn't expect that to have much of an immediate effect though bonds might go down a little bit in the short term but possibly even more in the long term as interest rates eventually head higher.  Another scenario is a very low interest rate environment (as today) with a stock market crash and not a lot of room for yields to go further down. Both stocks and bonds are influenced by current interest rates, interest rate expectations, current inflation, inflation expectations and stock price expectation.  Add noise and stir. It depends on why the stocks crashed. If this happened because interest rates shot up, bonds will suffer also. On the other hand, stocks could be crashing because economic growth (and hence earnings) are disappointing. This pulls down interest rates and lifts bonds.
If the equity market in the USA crashed, its very likely equity markets everywhere else would crash. The USA has a high number of the world's largest businesses and there are correlations between equity markets. So you need to think of equities as a global asset class, not regional. Your question is then a question about the correlation between equity markets and currency markets.  Here's a guess: If equity markets crashed, you would see a lot of panic selling of stocks denominated in many currencies, but probably the most in USD, due to the large number of the world's largest businesses trading on US stock exchanges. Therefore, when the rest of the world sells US equities they receive cash USD, which they might sell for their local currency. That selling pressure would cause USD to fall. But, when equity markets crash there's a move to safety of the bond markets. The world's largest bond markets are denominated in which currency? Probably USD. So those who receive USD for their equities are going to spend that USD on bonds. In which case there is probably no correlation between equity markets and currency markets at all. A quick google search shows this kind of thing "I can think of a few reasons for this. First, bonds are not as correlated with the stock market so having some in your portfolio will reduce volatility by a bit. This is nice because it makes you panic less about the value changes in your portfolio when the stock market is acting up, and I'm sure that fund managers would rather you make less money consistently then more money in a more volatile way.  Secondly, you never know when you might need that money, and since stock market crashes tend to be correlated with people losing their jobs, it would be really unfortunate to have to sell off stocks when they are under-priced due to market shenanigans. The bond portion of your portfolio would be more likely to be stable and easier to sell to help you get through a rough patch. I have some investment money I don't plan to touch for 20 years and I have the bond portion set to 5-10% since I might as well go for a ""high growth"" position, but if you're more conservative, and might make withdrawals, it's better to have more in bonds... I definitely will switch over more into bonds when I get ready to retire-- I'd rather have slow consistent payments for my retirement than lose a lot in an unexpected crash at a bad time!" "Bob should treat both positions as incomplete, and explore a viewpoint which does a better job of separating value from volatility. So we should start by recognizing that what Bob is really doing is trading pieces of paper (say Stocks from Fund #1 or Bonds from Fund #2, to pick historically volatile and non-volatile instruments.*) for pieces of paper (Greenbacks).  In the end, this is a trade, and should always be thought of as such.  Does Bob value his stocks more than his bonds?  Then he should probably draw from Fund #2.  If he values his bonds more, he should probably draw from Fund #1. However, both Bob and his financial adviser demonstrate an assumption: that an instrument, whether stock bond or dollar bill, has some intrinsic value (which may raise over time).  The issue is whether its perceived value is a good measure of its actual value or not. From this perspective, we can see the stock (Fund #1) as having an actual value that grows quickly (6.5% - 1.85% = 4.65%), and the bond (Fund #2) as having an actual value that grows slower (4.5% - 1.15$ = 3.35$).  Now the perceived value of the stocks is highly volatile.  The Chairman of the Fed sneezes and a high velocity trader drives a stock up or down at a rate that would give you whiplash. This perspective aligns with the broker's opinion.  If the stocks are low, it means their perceived value is artificially low, and selling it would be a mistake because the market is perceiving those pieces of paper as being worth less than they actually are.  In this case, Bob wins by keeping the stocks, and selling bonds, because the stocks are perceived as undervalued, and thus are worth keeping until perceptions change. On the other hand, consider the assumption we carefully slid into the argument without any fanfare: the assumption that the actual value of the stock aligns with its historical value.  ""Past performance does not predict future results.""  Its entirely possible that the actual value of the stocks is actually much lower than the historical value, and that it was the perceived value that was artificially higher.  It may be continuing to do so... who knows how overvalued the perceived value actually was!  In this case, Bob wins by keeping the bonds.  In this case, the stocks may have ""underperformed"" to drive perceptions towards their actual value, and Bob has a great chance to get out from under this market. The reality is somewhere between them.  The actual values are moving, and the perceived values are moving, and the world mixes them up enough to make Scratchers lottery tickets look like a decent investment instrument.  So what can we do? Bob's broker has a smart idea, he's just not fully explaining it because it is unprofessional to do so.  Historically speaking, Bobs who lost a bunch of money in the stock market are poor judges of where the stock market is going next (arguably, you should be talking to the Joes who made a bunch of money. They might have more of a clue.).  Humans are emotional beings, and we have an emotional instinct to cut ties when things start to go south.  The market preys on emotional thinkers, happily giving them what they want in exchange for taking some of their money.  Bob's broker is quoting a well recognized phrase that is a polite way of saying ""you are being emotional in your judgement, and here is a phrasing to suggest you should temper that judgement."" Of course the broker may also not know what they're doing!  (I've seen arguments that they don't!)  Plenty of people listened to their brokers all the way to the great crash of 2008.  Brokers are human too, they just put their emotions in different places.  So now Bob has no clear voice to listen to.  Sounds like a trap! However, there is a solution.  Bob should think about more than just simple dollars.  Bob should think about the rest of his life, and where he would like the risk to appear.  If Bob draws from Fund #1 (liquidating stocks), then Bob has made a choice to realize any losses or gains early... specifically now.  He may win, he may lose.  However, no matter what, he will have a less volatile portfolio, and thus he can rely on it more in the long run. If Bob draws from Fund #2 (liquidating bonds) instead, then Bob has made a choice not to realize any losses or gains right away.  He may win, he may lose.  However, whether he wins or loses will not be clear, perhaps until retirement when he needs to draw on that money, and finds Fund #1 is still under-performing, so he has to work a few more years before retirement.  There is a magical assumption that the stock market will always continue rewarding risk takers, but no one has quite been able to prove it! Once Bob includes his life perspective in the mix, and doesn't look just at the cold hard dollars on the table, Bob can make a more educated decision.  Just to throw more options on the table, Bob might rationally choose to do any one of a number of other options which are not extremes, in order to find a happy medium that best fits Bob's life needs: * I intentionally chose to label Fund #1 as stocks and Fund #2 as bonds, even though this is a terribly crude assumption, because I feel those words have an emotional attachment associated to them which #1 and #2 simply do not.  Given that part of the argument is that emotions play a part, it seemed reasonable to dig into underlying emotional biases as part of my wording.  Feel free to replace words as you see fit to remove this bias if desired." You say you have 90% in stocks. I'll assume that you have the other 10% in bonds. For the sake of simplicity, I'll assume that your investments in stocks are in nice, passive indexed mutual funds and ETFs, rather than in individual stocks. A 90% allocation in stocks is considered aggressive. The problem is that if the stock market crashes, you may lose 40% or more of your investment in a single year. As you point out, you are investing for the long term. That's great, it means you can rest easy if the stock market crashes, safe in the hope that you have many years for it to recover. So long as you have the emotional willpower to stick with it. Would you be better off with a 100% allocation in stocks? You'd think so, wouldn't you. After all, the stock market as a whole gives better expected returns than the bond market. But keep in mind, the stock market and the bond market are (somewhat) negatively correlated. That means when the stock market goes down, the bond market often goes up, and vice versa. Investing some of your money in bonds will slightly reduce your expected return but will also reduce your standard deviation and your maximum annual loss. Canadian Couch Potato has an interesting write-up on how to estimate stock and bond returns. It's based on your stocks being invested equally in the Canadian, U.S., and international markets. As you live in the U.S., that likely doesn't directly apply to you; you probably ignore the Canadian stock market, but your returns will be fairly similar. I've reproduced part of that table here: As you can see, your expected return is highest with a 100% allocation in stocks. With a 20 year window, you likely can recover from any crash. If you have the stomach for it, it's the allocation with the highest expected return. Once you get closer to retirement, though, you have less time to wait for the stock market to recover. If you still have 90% or 100% of your investment in stocks and the market crashes by 44%, it might well take you more than 6 years to recover. Canadian Couch Potato has another article, Does a 60/40 Portfolio Still Make Sense? A 60/40 portfolio is a fairly common split for regular investors. Typically considered not too aggressive, not too conservative. The article references an AP article that suggests, in the current financial climate, 60/40 isn't enough. Even they aren't recommending a 90/10 or a 100/0 split, though. Personally, I think 60/40 is too conservative. However, I don't have the stomach for a 100/0 split or even a 90/10 split. Okay, to get back to your question. So long as your time horizon is far enough out, the expected return is highest with a 100% allocation in stocks. Be sure that you can tolerate the risk, though. A 30% or 40% hit to your investments is enough to make anyone jittery. Investing a portion of your money in bonds slightly lowers your expected return but can measurably reduce your risk. As you get closer to retirement and your time horizon narrows, you have less time to recover from a stock market crash and do need to be more conservative. 6 years is probably too short to keep all your money in stocks. Is your stated approach reasonable? Well, only you can answer that. :) Bond aren't necessarily any safer than the stock market.  Ultimately, there is no such thing as a low risk mutual fund. You want something that will allow you get at your money relatively quickly. In other words, CDs (since you you can pick a definite time period for your money to be tied up), money market account or just a plain old savings account. Basically, you want to match inflation and have easy access to the money.  Any other returns on top of that are gravy, but don't fret too much about it. See also: Where can I park my rainy-day / emergency fund? Savings accounts don’t generate much interest. Where should I park my rainy-day / emergency fund? "In general, yes. If interest rates go higher, then any existing fixed-rate bonds - and hence ETFs holding those bonds - become less valuable. The further each bond is from maturity, the larger the impact. As you suggest, once the bonds do mature, the fund can replace them at a market price, so the effect tails off. The bond market has a concept known as ""duration"" that helps reason about this effect. Roughly, it measures the average time from now to each payout of the bond, weighted by the payout. The longer the duration, the more the price will change for a given change in interest rates. The concept is just an approximation, and there are various slightly different ways of calculating it; but very roughly the price of a bond will reduce by a percentage equal to the duration times the increase in interest rates. So a bond with a duration of 5 years will lose 5% of its value for a 1% rise in interest rates (and of course vice-versa). For your second question, it really depends on what you're trying to achieve by diversifying - this might be best as a different question that gives more detail, as it's not very related to your first question. Short-term bonds are less risky. But both will lose value if the underlying company is in trouble. Gilts (government bonds) are less risky than corporate bonds." "Market makers, traders, and value investors would be who I'd suspect for buying the stock that is declining. Some companies stocks can come down considerably which could make some speculators buy the stock at the lower price thinking it may bounce back soon. ""Short sellers"" are out to sell borrowed stocks that if the stock is in free fall, unless the person that shorted wants to close the position, they would let it ride. Worthless stocks are a bit of a special case and quite different than the crash of 1929 where various blue chip stocks like those of the Dow Jones Industrials had severe declines. Thus, the companies going down would be like Apple, Coca-Cola and other large companies that people would be shocked to see come down so much yet there are some examples in recent history if one remembers Enron or Worldcom. Stocks getting delisted tend to cause some selling and there are some speculators may buy the stock believing that the shares may be worth something only to lose the money possibly as one could look at the bankrupt cases of airlines and car companies to study some recent cases here. Circuit breakers are worth noting as these are cases when trading may be halted because of a big swing in prices that it is believed stopping the market may cause things to settle down." Short-term to intermediate-term corporate bond funds are available. The bond fund vehicle helps manage the credit risk, while the short terms help manage inflation and interest rate risk. Corporate bond funds will have fewer Treasuries bonds than a general-purpose short-term bond fund: it sounds like you're interested in things further out along the risk curve than a 0.48% return on a 5-year bond, and thus don't care for the Treasuries. Corporate bonds are generally safer than stocks because, in bankruptcy, all your bondholders have to be paid in full before any equity-holders get a penny. Stocks are much more volatile, since they're essentially worth the value of their profits after paying all their debt, taxes, and other expenses.  As far as stocks are concerned, they're not very good for the short term at all. One of the stabler stock funds would be something like the Vanguard Equity Income Fund, and it cautions: This fund is designed to provide investors with an above-average level   of current income while offering exposure to the stock market. Since   the fund typically invests in companies that are dedicated to   consistently paying dividends, it may have a higher yield than other   Vanguard stock mutual funds. The fund’s emphasis on slower-growing,   higher-yielding companies can also mean that its total return may not   be as strong in a significant bull market. This income-focused fund   may be appropriate for investors who have a long-term investment goal   and a tolerance for stock market volatility. Even the large-cap stable companies can have their value fall dramatically in the short term. Look at its price chart; 2008 was brutal. Avoid stocks if you need to spend your money within a couple of years. Whatever you choose, read the prospectus to understand the risks.