Alpha Kya Hai? Excess Return ki Kahani

Alpha Jensen ka formula se aata hai. Iska full name hai Jensen Alpha. Formula hai: Alpha = Portfolio Return minus [Risk Free Rate + Beta multiplied by (Market Return minus Risk Free Rate)].

Is formula mein jo bracket wala part hai usse Expected Return kehte hain. Yeh batata hai ki given the market movement aur your portfolio beta, aapko kitna return milna chahiye tha. Jo is expected return se upar milta hai woh alpha hai.

Simple example: Risk free rate 6 percent. NIFTY ne 14 percent diya. Aapka portfolio beta 1.2 hai. Toh expected return = 6 + 1.2 multiplied by (14 minus 6) = 6 + 9.6 = 15.6 percent. Aapke portfolio ne 20 percent diya toh alpha = 20 minus 15.6 = 4.4 percent positive alpha.

Efficient Market Hypothesis kehti hai ki publicly available information already stock prices mein reflect ho chuki hai. Agar sab investors same information pe same analysis kar rahe hain, toh koi bhi consistently alpha nahi generate kar sakta.

Data suggest karta hai ki 80 to 90 percent active mutual funds long term mein apne benchmark ko beat nahi karte after fees. Yeh number bahut telling hai. Iska matlab yeh nahi ki alpha exist nahi karta. Iska matlab hai ki alpha dhundna bahut hard hai aur sustain karna aur bhi hard.

Alpha ke sources jo work karte hain: information advantage jo jaldi milt hai, superior processing of available information, behavioral edges jaise discipline in drawdowns, aur structural inefficiencies jaise small cap stocks mein lower coverage.

Bahut log sochte hain unhone alpha generate kiya jabki woh actually sirf zyada risk le rahe the. Agar aapne small cap stocks mein invest kiya aur NIFTY se zyada return mila, toh check karo ki aapka portfolio beta kitna tha. Zyada return zyada risk ki wajah se bhi ho sakta hai.

Asli alpha risk-adjusted hota hai. Sharpe Ratio, Treynor Ratio, aur Information Ratio sab risk ko adjust karke alpha measure karte hain. Sirf raw returns dekhna misleading hai.

Ek aur common mistake hai survivorship bias. Agar hum sirf successful funds ya strategies ko dekhein aur failed ones ko ignore karein, toh hum sab ko alpha-generating lagega. Lekin woh funds jo band ho gaye, unka data often available nahi hota.