Structured products!
More or less, this is a deal with an investment bank where they take your money and hold onto it for a fixed term, while watching the level of a stock market index. If the index ever gets above a pre-determined "trigger level", they give you your money back early, with interest calculated at a fixed rate. If it never gets above the trigger level, then at the end of the term, they give you back your money, without interest. Unless the index has fallen below a "barrier level", in which case you don't get all your money back - you lose it in proportion to the fall in the index.
So, it's a bit like investing in the stock market - if the market goes up, you make money, if it goes down, you lose money - but rounded to fixed levels.
Here's an example:
http://www.marianainvestments.com/adviser/contact/view-plan/...
The term is 10 years, the index is the FTSE 100, the barrier level is 70%; there are three options for interest rates and trigger levels, and the safest, option 1, pays 8.55%, and has trigger levels like this:
Year Level
2 102.5%
3 100.0%
4 97.5%
5 95.0%
6 92.5%
7 90.0%
8 87.5%
9 85.0%
10 82.5%
So basically, if you think the FTSE 100 will hold its current level over ten years, or even decline slightly, you get a 8.55% per annum payout.
Or, if you think that it will make it to 105% of its current level, you could go for the full-blooded option 3, which pays out 14% per annum.
And bear in mind that a fall in the index only matters at the end of the term. If there's a crash, and the index has fallen to 50% of the current level by year 3, the product keeps running. If the index recovers to 87.5% of the current level five years after that, the product pays out! It literally cannot go tits up.