BMI, the ratio of weight in kilograms to the square of height in metres, is a common, if imperfect, gauge of whether someone is over- or underweight.

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International investors looking for countries to go stock picking in might be able to use the model, devised by Leila Heckman, as a means to over- or underweight a market.

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But rather than trying to over- or underweight according to where one believes the market is headed, dynamic strategies look at valuations which assets are over or undervalued in order to capitalize on market inefficiencies.

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