1.2.10
Intuition 30,000-foot viewSocho tumhe jaanna hai "aaj Indian stock market kaisa chal raha hai?" — lekin ~5,000+ listed companies hain. Sab ko track karna possible nahi. Toh tum sabse bade, sabse zyada trade hone wale companies ka ek chhota basket chunte ho, us basket ki combined value track karte ho, aur use index kehte ho. Jab basket upar jaata hai, hum kehte hain "market up hai."
Sensex = BSE (Bombay Stock Exchange) ke 30 sabse bade companies ka basket.Nifty 50 = NSE (National Stock Exchange) ke 50 sabse bade companies ka basket.
Dono barometers hain — market ke mood ka thermometer.
Definition Stock-market indexEk stock-market index ek single number hai jo ek chosen basket of representative stocks ki price movement ko summarize karta hai, ek base date par base value ke relative measure karke. Yeh tumhe market ki direction aur magnitude batata hai, actual rupee price nahi.
Definition Nifty 50 & Sensex
Nifty 50 : NSE ka flagship index, sectors mein phele 50 large, liquid companies ka. Base date 3 Nov 1995 , base value 1000 . Maintain karta hai NSE Indices Ltd .Sensex (Sensitive Index): BSE ka flagship index, 30 large companies ka. Base date 1978–79 , base value 100 . Maintain karta hai BSE / Asia Index .
YEH numbers kyun? 30 aur 50 itne bade hain ki diversified rahein (ek company crash kare toh poora index nahi bigdega) phir bhi itne chhote hain ki liquid aur track karna easy rahe.
Intuition Tum chahte ho ki basketrepresentative bhi ho aur tradeable bhi.
Agar tum ek tiny illiquid company ko index mein daalo, uski price barely change hogi (koi trade hi nahi karta), toh woh ek dead weight ban jaayegi jo tumhe mislead karegi. Isliye indices mein size + liquidity + sector spread zaroori hoti hai.
Key filters (dono indices ki spirit similar hai):
Large market capitalization — badi companies economy ko dominate karti hain.High liquidity — impact cost se measure hoti hai (jab tum trade place karte ho toh price kitna move karta hai). Low impact cost = liquid.Listed & traded minimum period ke liye, India mein domiciled, regular financials.Sector representation — Banking, IT, Energy, FMCG, Auto, etc., taaki koi ek sector unfairly dominate na kare.
Companies ko periodically review kiya jaata hai (Nifty semi-annually) aur rebalanced kiya jaata hai — laggards bahar jaate hain, risers andar aate hain.
Dono Nifty aur Sensex Free-Float Market-Capitalization Weighted method use karte hain. Chaliye ise step by step samajhte hain.
Step 1 — Ek company ka market cap.
Market Cap = ( Share Price ) × ( Total Shares outstanding ) Kyun? Yeh company ki total rupee value hai.
Step 2 — Free-float adjustment.
Saari shares freely trade nahi hoti. Promoters, government, aur locked-in holders daily nahi bechte. Sirf free-floating shares (public ke liye available) hi price drive karti hain. Toh hum inhi se weight karte hain.
Free-Float Factor (IWF) = Total shares Freely tradeable shares Free-Float Mcap = Price × Total Shares × IWF Free-float kyun? Kyunki promoter-held shares ko investors actually khareed nahi sakte, toh unhe ek tradeable index mein company ki weight inflate nahi karni chahiye.
Step 3 — Basket sum karo, base se compare karo.
Index = Base Market Cap ∑ i = 1 N Free-Float Mcap i × Base Index Value
Sensex ke liye: N = 30 = 100 N = 50 = 1000
Intuition "Divisor" kyun, fixed base kyun nahi?Agar koi company bonus deti hai, uski share price half ho jaati hai lekin economically kuch nahi badla. Index ko drop nahi karna chahiye. Toh maintainer divisor ko tweak karta hai taaki aisi corporate actions absorb ho sakein — index continuous bana rahe.
Worked example Example 1 — Ek mini 2-stock index banaoBase day: Company A price ₹100, 1000 shares, IWF 0.5. Company B price ₹200, 500 shares, IWF 0.8.
Base index = 100 set karo.
Step — base free-float mcap. Kyun? Humein denominator chahiye.
A: 100 × 1000 × 0.5 = 50 , 000 200 × 500 × 0.8 = 80 , 000 130 , 000
Aaj: A ₹120 par pahuncha, B ₹200 pe hi raha (shares & IWF same).
A: 120 × 1000 × 0.5 = 60 , 000 80 , 000 140 , 000
Step — index. Kyun? Base se ratio × base value.
Index = 130000 140000 × 100 = 107.69 7.69% upar hai.
Worked example Example 2 — Free-float kyun matter karta haiCompany X: price ₹500, 1,000,000 shares, lekin promoters 80% hold karte hain (IWF = 0.20).
Full mcap = 500 × 1 0 6 = ₹50 Free-float mcap = 50 cr × 0.20 = ₹10 Yeh step kyun? Index mein, X sirf ₹10 cr ki weight count karega, ₹50 cr ki nahi — kyunki sirf 20% actually trade ho sakta hai. Yeh promoter-heavy company ko dominate karne se rokta hai.
Worked example Example 3 — Bonus issue & divisorCompany 1:1 bonus deti hai. Shares double, price half → free-float mcap reality mein unchanged lekin price ki rounding ki wajah se summed numerator shift ho sakta hai. Maintainer divisor reset karta hai taaki corporate action ke baad index same value dikhaye. Kyun? Koi wealth create nahi hui; index continuous rehna chahiye.
Common mistake "Zyada index number matlab better/bigger market."Kyun sahi lagta hai: Sensex ≈ 75,000 jabki Nifty ≈ 23,000, toh Sensex bada lagta hai.
Fix: Unke bas alag base values hain (100 vs 1000) aur alag base dates . Level arbitrary hai; sirf % change comparable hai. Nifty aur Sensex usually % mein saath chalte hain.
Common mistake "Index mein har company ka equal weight hota hai."Kyun sahi lagta hai: "50 stocks, toh har ek 2% hai." Intuitive hai lekin galat.
Fix: Weighting free-float market cap se hoti hai. HDFC Bank ya Reliance jaisi giant 10%+ ho sakti hai jabki chhota member <1% hoga. Bade fish index ko zyada move karte hain.
Common mistake "Total shares weight determine karte hain."Kyun sahi lagta hai: Zyada shares = badi company, fair lagta hai.
Fix: Sirf freely tradeable (free-float) shares count hote hain. Promoter-locked shares IWF ke zariye exclude hoti hain.
Common mistake "Index sirf prices par depend karta hai."Kyun sahi lagta hai: Index tab upar jaata hai jab prices upar jaati hain.
Fix: Yeh shares outstanding, free-float factors, divisor, aur composition changes par bhi depend karta hai — koi company enter/leave kare toh sab kuch reshuffle ho jaata hai.
Sensex vs Nifty 50 mein kitni companies hoti hain? Sensex = 30 (BSE); Nifty 50 = 50 (NSE).
Dono Sensex aur Nifty kaunsi weighting method use karte hain? Free-float market-capitalization weighting.
Free-float market cap define karo. Price × Total shares × Investable Weight Factor (freely tradeable fraction).
Promoter-held shares ko index weight se exclude kyun karte hain? Woh freely tradeable nahi hain, isliye unhe ek tradeable index mein company ki weight inflate nahi karni chahiye.
Nifty 50 ki base date & base value? 3 Nov 1995, base value 1000.
Sensex ki base period & base value? 1978–79, base value 100.
Tum Sensex level (75000) vs Nifty level (23000) directly compare kyun nahi kar sakte? Alag base values/dates hain; sirf % change comparable hai.
Selection mein 'impact cost' kisliye use hota hai? Ek liquidity measure — jab trade place kiya jaaye toh price kitna move karta hai; low impact cost = liquid = eligible.
Bonus/split ke dauran 'divisor' kyun adjust kiya jaata hai? Index ko continuous rakhne ke liye jab corporate action se koi real wealth create nahi hoti.
Master index formula? Index = (Σ Pᵢ·Sᵢ·IWFᵢ / Base Mcap) × Base Value.
Nifty 50 ke liye kaunsi exchange aur maintainer hai? NSE, maintain karta hai NSE Indices Ltd.
Kya ek company crash hone se index barbad ho jaata hai? Nahi — 30/50 stocks aur kai sectors mein diversification isse cushion karta hai.
Recall Feynman: 12-saal ke bachche ko samjhaoSocho ek class mein 5000 students hain, itne zyada track karna mushkil hai. Toh tum 50 sabse lambe, popular kids chunte ho aur har roz unki average height measure karte ho, weighted by kitna woh actually bahar khelne jaate hain . Agar aaj woh average pehle din se badi hai, tum kehte ho "class badi ho gayi!" Woh measured number index hai. Sabse lambe kids (sabse badi companies) number ko sabse zyada move karte hain. Agar koi twins mein split ho jaaye (bonus/split), tum apna math tweak karte ho taaki number fake reason se jump na kare. Sensex 30 kids dekhta hai, Nifty 50.
"3-B-B" aur "5-N-N" : 3 0 stocks → B SE → B ase 100 (Sensex). 5 0 stocks → N SE → N ineteen-95 base 1000 (Nifty). Yeh bhi: "Free-Float = sirf woh jo Float (trade) karta hai woh count hota hai."
What is a Share and Ownership — index members woh shares hain jo tum own kar sakte ho.Market Capitalization — index ki weighting ka engine.Free-Float vs Total Shares — IWF concept.BSE vs NSE Exchanges — Sensex aur Nifty ke ghar.Index Funds and ETFs — poore basket mein ek saath invest kaise karo.Corporate Actions - Bonus, Split, Dividend — divisor kyun exist karta hai.Sector Diversification — basket industries mein kyun phela hota hai.
Basket of representative stocks
High liquidity via low impact cost
Price x Shares x Free-float factor
