Big-buying day ke baad: kya stock chalta hai?
7 min read · data: 437-stock NSE universe · descriptive study, not advice
“Aaj isme bahut bada volume aaya, stock 4% upar band hua, day ke high ke paas — bada paisa ghusa hai, ab yeh chalega.” Yeh shayad market ki sabse natural lagne wali soch hai. Agar koi bada player itna kharid raha hai, toh use kuch pata hoga, na?
Humne isko seedha test kiya. Yeh measurement hai, prediction nahi. Aur jawab hamari apni ummeed ke bhi khilaaf aaya.
”Big-buying day” ki definition
Ek stock-day ko big-buying day maana agar teeno baatein sach hon:
- Volume ≥ 2× pichhle 20 din ka average,
- Close ≥ +2% pichhle close se,
- Close din ki range ke upar wale ek-tihai mein (yaani close tak kharidari rahi).
Ek zaroori practical rule: aapko yeh footprint din khatam hone ke baad dikhta hai. Toh entry agle din ke open pe maani, us close pe nahi. Aur har result ko usi din ke poore market ke average (drift) se compare kiya, zero se nahi.
Data: 210 F&O stocks, 2014 – Jul 2026, 13,796 big-buying days. Robustness ke liye 508 stocks ka broad universe bhi (34,361 days).
Result: agle din halki si girawat
| Horizon | Signal ka avg return | Win rate | Same-date market drift | Edge vs drift |
|---|---|---|---|---|
| Agla din (open → close) | −13.9 bps | 43.5% | −9.2 bps | −4.7 bps |
| 5 din | +19.4 bps | 48.1% | +30.8 bps | −11.3 bps |
| 20 din | +188 bps | 54.2% | +183 bps | +5.3 bps |
(100 bps = 1%.)
Seedhi bhasha mein:
- Agle din stock thoda wapas deta hai. Win rate 43.5% — coin flip se kam. Random dino ke 1,000 bootstrap samples mein yeh result neeche ke 1.8% mein tha.
- 5 din mein stock chadhta hai, lekin market se kam. +19 bps vs market ka +31 bps.
- 20 din mein bas market ke saath chalta hai. +5 bps ka farak noise hai — era badalne pe iska sign ulat gaya (2016–21: −31 bps, 2022–25: +56 bps).
Broad 508-stock universe mein fade aur saaf tha: agla din −20.5 bps, win rate 41.9%. Chhote, kam liquid stocks sabse zyada fade karte hain.
”Zyada paisa = zyada continuation?” Nahi.
| Volume kitna guna | Days | Agle din edge vs drift | 5 din edge |
|---|---|---|---|
| 2–3× | 7,576 | −7.1 bps | −15.6 bps |
| 3–5× | 4,031 | −3.4 bps | −6.3 bps |
| 5×+ | 2,189 | +1.2 bps | −5.9 bps |
Sabse bade spikes thoda kam fade karte hain, lekin koi bucket “continuation” nahi dikhata.
”Lekin delivery dekho — asli paisa vs intraday churn”
Yeh sabse achha sawaal hai. Idea: agar volume ka bada hissa delivery mein gaya (log share ghar le gaye, intraday mein khareed-bech nahi kiya), toh woh “real accumulation” hai. July mein humare paas sirf 30 din ka delivery data tha (137 days — kuch kehne ke liye kam). Ab humare paas May 2023 – Sep 2026 ka delivery data hai, ~500 stocks, 11,218 big-buying days. Toh dobara test kiya:
| Big-buying day ka delivery % | Days | 5 din excess vs drift | 10 din excess vs drift | 10 din win rate |
|---|---|---|---|---|
| Sab | 11,218 | −0.22 pp | −0.19 pp | 49% |
| Delivery apne median se zyada | 2,428 | −0.10 pp | −0.07 pp | 51% |
| Delivery median ka 1.3× se zyada | 556 | −0.04 pp | −0.12 pp | 52% |
| Delivery median ka 0.8× se kam (churn) | 6,115 | −0.32 pp | −0.38 pp | 48% |
(Base rate: kisi bhi random din ke baad 10 din mein 50.4% stocks upar the.)
Yahan ek honest nuance hai: delivery farak daalti hai, lekin “rocket” nahi banati.
- Kam delivery wale big days (intraday churn) clearly market se peeche reh gaye.
- Zyada delivery wale big days bas market ke barabar chale — negative drag gayab, lekin koi extra continuation nahi.
Toh “asli paisa” ka footprint aapko bura signal hone se bachata hai, achha signal nahi banata.
Kyun lagta hai ki chalta hai?
Kyunki big-buying din khud upar hota hai (definition se hi +2%), aur mahine bhar mein stock market ke saath upar drift karta hai. Aankh “woh upar gaya” yaad rakhti hai. Lekin us din ke baad ka extra information ek halka fade hai. Bada volume ek move ka lakshan hai jo ho chuka — agle move ka signal nahi.
Kya dekhein (kya kharidein nahi)
- Big volume day ko “kuch ho raha hai” ki tarah dekhiye — volatility aur attention ka sign. Direction ka nahi.
- Delivery % saath mein dekhiye: kam delivery + bada volume = zyada tar churn.
- Humare /stocks/ pages pe volume aur delivery context daily update hota hai.
The limitation
Delivery wala hissa 2023–26 tak simit hai (lagbhag 3.4 saal) aur ~12 cuts test kiye gaye — multiple testing ka risk hai. Big-buying definition ek hai; doosri definitions (jaise turnover 3×) ne same jawab diya. Friction ke baad (cash ~0.30% round-trip) agle din ka fade bhi trade karne layak nahi. Base rates past describe karte hain; future predict nahi karte.
Methodology note. Main study (Jul 2026): yfinance daily data, 490 stocks with ≥250
bars, 2014 → 2026-07-20; F&O subset 210 names; forward returns from next open (1d =
close/open of t+1; 5d, 20d = close t+h / open t+1); nulls = same-stock base rate,
date-matched universe drift, 1,000-draw random-day bootstrap. Source: tietiy internal
research (big_buying_continuation_2026-07). Delivery split (Oct 2026): NSE
bhavcopy-derived daily prices + delivery % for ~500 stocks, big-buying days May 2023 –
Sep 2026; delivery baseline = own trailing-20-session median; 10-day forward windows
with any |daily move| > 20% dropped (split/bonus artifacts); excess = return minus
same-date mean of all stocks.