"Therefore you should recognise that if you’re adding corporate bonds in then you might want to reduce your equity risk elsewhere, so there is a trade-off," said Mr Dekell.

If an investor already believes they have the right amount of equity risk before investing in corporate bonds and they want to move into corporate bonds, he said, they need to offset that risk somewhere else.

"You don’t want to be doubling up on your risks by adding corporate bonds on top of the equity risk you already had, thinking you’re putting defence assets into the portfolio.

"If you are looking for defence, government bonds are your best source of defence, particularly over a short-term time horizon."