All I can say is that I am topping up on these three myself. It is your choice whether to follow or not.

Some background info:

When one is a follower of Markowitz Modern Portfolio Theory (MPT), there are a few parameters which the theory suggest to look at when buying a position in any risky asset. It does not teach one about expensive or cheap (that is another school of thought - namely the Fundamental Analysis School of Thought).

MPT always look at taking position in a risky asset based on how less risky it is compared to peer. It essentially teaches to take a position that gives the best return per unit of risk (i.e., the most optimum risk to reward position).

Let's say a fund is perceived to be expensive, but it has the least volatility. Another fund may be selling at bargain price, but its price fluctuate wildly. MPT will still advocate the "perceived" expensive fund. It favours stability.

Hope this helps explain the MPT rationale.

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