Strategy reference

Classic Screens — Canonical Reference

data; proxies labeled, value shown with its recorded failure numbers · Governing decision(s):

· (factor doctrine) · Guardrail #8 (primary sources) · Reconciled: 2026-07-14 ·

Origin: 📚 CLASSIC (famous public strategies — Magic Formula · CANSLIM · Piotroski · Coffee Can · GARP · Graham · Quality · Low-Vol — re-proven on our PIT data). See the origins notes.

Charter: the strategy ledger · factor-league sibling

One-line definition: The famous, name-brand equity strategies (Magic Formula, CANSLIM,

Piotroski, Coffee Can, GARP, Graham, Quality, Low-Vol) catalogued and run as live top-25 rosters

over the NSE universe — descriptive research shortlists, never buy lists.

1. What it is

A menu of the public, citable stock-selection strategies the professional world respects, each

made concrete as a screen the analyst can actually run and inspect at /dash/classics. It is the

sibling of the Factor League (/dash/factor-league): the Factor League ranks the raw factor

*families* (momentum, value, quality, low-vol) by the return/vol + alpha we measured on 14 years of NSE

data; Classic Screens implements the named, multi-signal *strategies* built on those factors and

surfaces their current participants.

Every strategy is expressed as our closest faithful reading of the original rule, run point-in-time so

a roster contains only what was knowable on the scan date.

2. Our variation vs. the standard technique

We run each rule as published where our data allows, and say so plainly where it does not. The

canon splits by what our primary-source data can compute point-in-time:

The doctrine constraint (README §"doctrine") is enforced here: **price strength is the only gross

forward-return engine on our data; value and quality are context, not fundable rankers.** So the value

strategies are presented *with* their recorded results, not as recommendations.

3. How it works (methodology)

Nightly, famous_strategies.refresh takes the liquid universe from the latest momentum_scan

(turnover ≥ ₹5cr), joins each name's point-in-time fundamentals via

fundamentals_asof.as_of_fundamentals (with the latest

bhav close as price), and applies each strategy's gate + ranking. Composite strategies rank by

cross-sectional percentile blends (the pctrank helper); single-axis strategies rank by their one

metric. Each produces a top-25 roster written to the isolated classic_roster table. The exact

thresholds live in the code, not here (calculations-and-weights doctrine — do not restate constants).

4. Status, validation & honesty fence

DESCRIPTIVE-ONLY. These rosters are research shortlists, not signals or advice. No claim is made

that any of them beats Nifty-500 buy-and-hold net of realistic cost — our own testing found the

opposite for most, and the value family worst of all:

• Deep value / book-yield is HARD-REJECTED on our data (negative alpha, beta ≈ 1.54, MaxDD ≈ −82%

— the exact numbers are in the strategy ledger § BLOCKING FAILURE MODELS).

The Graham roster and the Magic Formula value leg are shown as a caution, next to that record.

• Momentum/RS leadership (CANSLIM's engine) is a real *gross* selection lens but its edge is a

known risk-premium beta, not skill, and it dies on cost at scale (ledger § cost realism).

• Quality ranks nothing on its own (α ≈ 0); it earns its place as a filter .

The one participation-fundable corner remains quarterly large-cap LOWVOL_MOM — see the Factor League

and the momentum riskadj notes. This page may not soften any of the above without a new

pre-registered, leak-free study recorded in the ledger (skill failure-ledger).

5. Where it lives (code · routes · DB · timers)

• Compute: the famous strategies code —

pure scorers + refresh; owns classic_roster. CLI --refresh / --selftest.

• View: the classics view code → /dash/classics

(roster: ?s=<strategy>; CSV: ?s=<strategy>&fmt=csv).

• Registry: the lens registry code key classics (altitude strategies); durable mount in

v2_surfaces._ROUTER_SPECS.

• DB: isolated classic_roster in {retired}.db (no the db code edit). Timer: wired alongside the

nightly momentum_scan / factor_league refresh (after momentum_scan lands).

• Tests: an automated test; the route is

covered by the no-orphan an automated test and this doc by

an automated test.

6. Data & provenance

🔴 Source disclosure (Guardrail #8 — "disclose it where shown"). Split the claim in two, because

they are not the same:

Measured 2026-07-15: 789,838 rows in fundamentals_history — 717,895 Screener-sourced (`source IS

NULL), 66,686 NSE-XBRL-CONSO, 5,257 NSE-XBRL-SA`. This estate adds no new Screener dependency

(it reads the existing archive; it never calls the screener code), but it does *rest* on one, and saying

"read point-in-time through fundamentals_asof (real BSE/NSE filing date…)" describes only the

timing gate — it must not be allowed to imply a primary origin. The /dash/classics page

carries the same disclosure (_PROVENANCE), dated on purpose: the split shifts as XBRL lands, and an

undated "91%" would itself go stale into an untruth.

This makes phase 2 a remediation, not just a feature: the annual-XBRL tags below are the route

*off* the 91% vendor dependency (forward from 2026-04), not merely the unlock for Acquirer's Multiple.

All fundamentals are read point-in-time through fundamentals_asof (real BSE/NSE filing date where

captured, else a conservative calibrated lag — no look-ahead). Price is the latest NSE bhav close

(primary). Two known data gaps (Guardrail #8-clean to close via XBRL, not Screener):

1. No point-in-time enterprise value (needs PIT cash + clean share count) → blocks true Magic

Formula (EBIT/EV yield → we substitute E/P) and all of Acquirer's Multiple (EV/EBIT).

2. No cash-flow statement / current-asset split → blocks Piotroski's cash-flow trio (we ship an

F5-of-9) and Graham's current-ratio leg.

Closing both is the phase-2 task: add cash-flow + enterprise-value + current-asset tags to

fundamentals_xbrl.extract_for and backfill — then Magic Formula, Piotroski, Graham and Acquirer's

Multiple upgrade to full fidelity. This must NOT be done by extending the screener code (Guardrail #8).

✅ Feasibility SETTLED by a live probe — the ANNUAL NSE XBRL filing carries all of it.

A quarterly instance is P&L-only (65 tags; SEBI LODR requires the balance sheet + cash-flow

statement annually, not quarterly). An annual instance has 232 tags including

CashAndCashEquivalents (→ enterprise value → true EBIT/EV and Acquirer's Multiple),

CashFlowsFromUsedInOperatingActivities (→ Piotroski's missing CFO trio → the full 9), and

CurrentAssets/CurrentLiabilities (→ Graham's current-ratio leg). Annual is the correct cadence —

Greenblatt, Piotroski and Graham are all annual rules. Caveat: XBRL is forward-only (2026-04→),

so this unblocks the RULES going forward; it does not deepen history (see §2 note on the ~2015

breadth cliff, which is a separate, unsolved data problem).

Reconstructed portfolios

Each rule also runs as a NAMED, BACKDATABLE model portfolio via

the classic portfolios code — an additive sibling of the

auto_portfolios engine (reusing its clock/gate/band/cost/NAV math verbatim; the classics are NOT

admitted into that estate because they do not clear its "superior Sharpe + beats Nifty" bar). The

missing piece it adds is a point-in-time fundamentals panel. Books are charted only with **5+

years** of history (gate on YEARS, never rebalance count — 20 rebalances is 5y quarterly but 1.7y

monthly). Adoptable from /dash/tracker/model-books with today as entry — a reconstruction is

never written into a real book.

7. Terminology canon

8. Decision & session history

• / (2026-07-14): built the Classic Screens catalog + /dash/classics runnable lens

(5 full + 3 proxy rosters), this canonical page, and the phase-1/phase-2 split. Sequencing chosen by

the desk: ship the computable strategies now, close the XBRL EV + cash-flow gap next.

• / W-1462 (2026-10-03, under ): on the new site, what is still built on the

vendor fundamentals archive is retired, not rebuilt: the seven fundamentals screens' reconstructed book

records (Low-Volatility's prices-only book stays) and the Coffee Can screen (its rule needs five years of

sales growth; the exchange filings begin in 2019). They leave every listing, link, comparison row and

registry alias; the code stays, and /strategies/library?s=coffeecan still serves the withheld notice.

The six rosters rebuilt on exchange filings (Quality, CANSLIM, GARP, Magic, Piotroski F5, Graham; W-0420

row 12) stay. Classic /dash/classics is untouched (Guardrail #14). Reversible: re-list a screen once

the filings are deep enough for its rule.

9. Open items / frozen work

• Phase 2 (data): XBRL cash-flow + enterprise-value + current-asset tags → upgrades Magic Formula,

Piotroski, Graham; unlocks Acquirer's Multiple (currently reference-only).

• Home-exposure: deliberately not a home tile in phase 1 (descriptive catalog; revisit once

full-fidelity value screens land).

• Optional: a churn feed (roster entries/exits) like the Factor League's, if the rosters prove useful.

10. Sources of truth

• Result numbers / failure record: the strategy ledger (never duplicated here).
• Factor doctrine: the momentum riskadj notes · README §doctrine.
• Metric definitions: the metrics glossary.