As you can see in the graph below, when combining such assets, returns generally shift to the lower right: higher return and lower risk (as measured by standard deviation).

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Why not invest 100% in these supposedly higher-return, lower-risk funds?

FORBES: Expert View

"Floating rates are lower risk and lower return, " says David Battersby, investment manager at stockbrokers Redmayne-Bentley.

WSJ: A Secure High-Yield Alternative?

But Markowitz's heirs have gone on to show that it is possible to combine securities in a portfolio in order to achieve a higher return as well as a lower risk.

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Passive investing offers the already-rich a steady return with less risk and, ultimately, lower costs.

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This is because any remedy would require that the sukuk be changed so that the sukuk holder shoulders a risk of loss, or of lower return, in years where the venture did not meet earnings expectations.

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My return expectations are lower since I do not need to take the risk.

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They return about the same as long-term bonds with lower interest-rate risk and pay substantially better than short-term bonds.

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You might be able to get a better return by taking on some risk - but you could lose money or make lower returns than you expect if your investments are not successful, especially if you might need to get at your money in the next few years.

BBC: There are lots of ways to put some money away for the future.

This assumes that in retirement the couple switches to a lower-risk, conservative portfolio of government and high grade corporate bonds earning on average a real return of just 3%.

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