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VAR (Value at Risk) 與個股投資
定義:
In finance, the term "VaR" refers to Value at Risk, a statistical measure used to quantify the potential loss of an investment portfolio or firm over a specific time period with a given probability. It answers the question: "What is the maximum potential loss, at a specific confidence level, over a defined timeframe?". For instance, a portfolio with a one-day VaR of $1 million at a 95% confidence level means there's a 5% chance the loss will exceed $1 million.
延伸: 個股購買時,影響未來一段時間(比如一年)股價因數大致有:大盤變化(beta體現在這裏),股票盈利變化(比購買時變好或者變差),其它影響股價的因素(比如EV credit),等等。
VAR: 如果按正常估計的概率得到的VAR比較小,同時預期盈利高,(還可以加上div), 那麽是一個好的購買。相反,如果這個數值比較大,或者擁有過程中變大,那麽就要小心了。
Loss 概率體現在購買者對風險的忍耐度。買lottery 和買T bill 是兩個極端。買小藥股和買WMT也是非常好的對比。
有空瞎算算,挺有意思的。
https://www.investopedia.com/terms/v/var.asp