You can buy a fund when the valuation is overvalued, and it is not recommended to buy a fund when the valuation is high. Because high valuation means that this asset is not cheap, the future valuation will generally fall and investors will suffer losses.

If investors have held it before, they can continue to hold bubbles that enjoy valuation. Because a high valuation does not mean that it will fall immediately, it is possible that the valuation will be higher. In the case that investors have floating profits, it is not too late to wait until the bubble is punctured.