Standard deviation vs. Semi standard deviation as measures of risk in finance

Some suggest that semi standard deviation is more relevant because it doesn’t incorporate returns above the mean or any threshold in the computation of risk. I have calculated the semi standard deviation (from the mean and from a threshold) and experimented with both n and n-1 in the denominator, and to my surprise the value of the semi standard deviation was higher than the value of the standard deviation. Under what circumstances the semi standard deviation exceeds the standard deviation? Do practitioners use the semi standard deviation in portfolio management?

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Risk = the potential for you to lose money / principle, not volatility (in my mind)

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