Disclaimer: I am not a financial adviser and you need to do your own research.
I won't repeat this good article on investing for effective altruists: https://80000hours.org/2015/10/common-investing-mistakes-in-the-effective-altruism-community/ . But one of the key ideas is if you are investing for yourself and you are young, or if you are investing for charity, temporary falls in value should not worry you. Taken even further, if there is a big payoff, but some chance of losing all your money, this can still be a good idea. This means that you are risk neutral, and just care about the expected (probability weighted) outcome. If you are like this, then I have an investment opportunity you may be interested in.
It is three times leveraged Russia. The Russian stock market has fallen precipitously, and it has fallen even more so from the US perspective because of currency changes. If it recovers to fair market value (mean reversion) over seven years, the value of your investment would be about four times as much. However, with three times leverage, even taking into account that you need to pay interest on the implicit loan, one would expect more like 50 times the money. Now there are impacts of volatility that I do not fully understand that could reduce this. But I have seen a 3X leverage produce 15 times as much money as the initial investment in 5 years and it was not quite as good an opportunity as Russia.
The downside of Russia is not just the normal potential for temporary loss of money. It is also possible that there could be a forced sell out of foreign assets, freezing of assets, or even seizing of assets, depending on international relations. So this is definitely not for the faint of heart.
But if you are risk neutral like I am, you may want to give it a try. The ticker is RUSL. I just put a significant fraction of my portfolio into it today.
Also, one could even argue that helping out Russia when it is worst off could prevent Russia from doing desperate things, so there may be global catastrophic risk benefits.
Update: March 17, 2016:
If you decided to invest when I did, congratulations - you have made 80% on your money in less than two months! This now means that the expected long-term return is significantly lower. Then when you include the volatility drag (see discussion below), it is not clear that this leveraged investment is better than just unleveraged Russia. So it might make sense to start phasing out of leveraged Russia and buying ERUS, especially if it is a large percent of your portfolio. On the other hand, if you think that oil price will continue rapidly reverting towards the long-term marginal cost of production, since Russia is highly correlated with oil price, you may want to stay in leveraged Russia longer.
Thanks for the link. It sounds like Brian is saying that margin works in a way like taking out a loan. If you had $100,000 to start with and took out a loan for $200,000 and invested all $300,000, and the value went to 50%, your net worth would be $-50,000. My understanding of these leveraged funds is that you cannot go negative. You can rebalance yourself to avoid this, but that is a lot of work.
Check out http://finance.yahoo.com/echarts?s=TECL+Interactive#symbol=TECL;range=my . This is the 3X investment that produced 15 times as much money, and we got that the underlying asset had a growth ratio of roughly the cube root of 15. So basically leverage is not multiplying the returns by three, but raising to the third power. You can see this with a simple case of underlying investment return of 10% per year over 20 years give 6.7 times as much money. However, if you double the annual return to 20%, after 20 years you get 38 times your money (and really doubling your daily return would mean 21% annual). It is does not quite achieve this I believe because of the impact of volatility (Brian says alternating days of gains and losses hurt) and of course the fees and interest on the implicit loan.
If that's true then it sounds like the way ETFs implement leverage is completely different from how margin works. I don't really know how ETFs implement leverage though.