33 rules
of the tape.
The operating doctrine of TAPE 33. Each rule is a maxim. Each maxim was earned the hard way. Click any rule to expand the field-note that motivates it.
01.Read the tape, not the news.▾
The headline arrives after the print. The print is the truth.
02.The float is the constraint.▾
Market cap can be huge while the tradable float is microscopic. Always check both — short interest and days-to-cover only make sense against the float, not the share count.
03.Settled short interest beats daily short volume.▾
Daily short volume includes intraday market-maker flow that's flat by the close. Settled SI is T+2 reality. Use settled for the read; use daily as a proxy when settled is stale.
04.The 13F is two months stale. Use it anyway.▾
Statutory filing window is 45 days post-quarter-end. Funds have moved by the time you read it. But the quarterly delta still tells you who was committed at the close of the period — and that is what compounds.
05.Insider transactions speak in clusters, not solos.▾
One sale is housekeeping. Three sales from three executives in two weeks is a signal. Cluster within 30 days, on the same side, before reading anything into it.
06.Material events live in 8-K item codes. Memorize them.▾
Item 1.01 is a definitive agreement. Item 2.02 is earnings. Item 5.02 is a departure. Item 8.01 is a discretionary disclosure. The code tells you what happened before you read a single sentence.
07.Catalysts within 30 days are tradable. Beyond, they are stories.▾
The catalyst calendar gets noisy past a month — too many things move. Inside 30 days, the variance is bounded enough to size against.
08.Foreign ADRs report ordinary shares. Divide by the deposit ratio.▾
BABA reports 18.58B ordinary shares. The ADS represents 8 ordinaries. The ADS-equivalent count is 2.32B, not 18.58B. Multiply that by the ADS price. SEC Form F-6 gives you the ratio.
09.Tiingo for prices. Yahoo for the gaps. Stooq for the backfill.▾
Tiingo Power is the live feed. When Tiingo returns a 200 with a capped message, fall through to Yahoo. When Yahoo is rate-limited, fall through to Stooq for everything except the last 1-2 trading days.
10.The synthesis must cite. Without citation, it is fabrication.▾
An AI sentence with no link is a guess. An AI sentence with a link is research. The link is the load-bearing element. The prose is decoration.
11.RAG over chat. The chunks are the truth, the model is the voice.▾
Retrieve relevant chunks first. Condition the generation on those chunks. The model's job is to translate, not to invent. Anything that contradicts the chunks is hallucination.
12.SEC EDGAR at 8 RPS. Exceed 10 and the IP is blocked for ~10 minutes.▾
The documented rate limit is 10. The safe limit is 8. The IP-block timeout is silent — no error code, just an empty response window for the next 10 minutes.
13.Float can be stale. Settled SI cannot lie.▾
Float is updated quarterly at best, often slower. Settled SI is reported twice a month. The pct_of_float ratio is only as fresh as the slower number — and that's almost always float.
14.Congressional trades disclose on a 45-day lag. Treat them as anchors, not signals.▾
The STOCK Act gives Congress 45 days to disclose a transaction. By the time you see Pelosi's NVDA buy, the stock has moved. Use the disclosure as a sentiment anchor — it tells you what conviction was being placed two months ago.
15.PR feeds front-run earnings by minutes, not hours.▾
GlobeNewswire and PRNewswire publish PR before the 8-K is accepted by EDGAR. Watch the wire for material-event headlines on biotech and small-cap pharma — they're the first signal.
16.The biotech catalyst calendar is biotech-only. Don't query it on Microsoft.▾
FDA AdComm and PDUFA dates exist for pharma + biotech. Querying them for an operating company returns noise — usually false negatives that look like empty calendars but are actually irrelevant calendars.
17.Cash + ST investments is the runway numerator. Quarterly OCF is the denominator.▾
Runway = (cash + short-term investments) / |quarterly operating cash flow|. If OCF is positive, the company is profitable and runway is infinite — don't render a number, render PROFITABLE.
18.PEG can be null. P/E can be negative. Both are signals.▾
PEG requires forward earnings estimates; for unprofitable names there is no PEG. P/E flips negative when earnings flip negative. Neither is a bug. Render the null with a tooltip that explains why.
19.Days-to-cover is short volume ÷ ADV. % of float is short interest ÷ float. Don't confuse them.▾
These measure different things. Days-to-cover is liquidity (how many trading days for shorts to exit). % of float is conviction (how much of the tradable supply is short). Surface both, label them differently, never let the user mistake one for the other.
20.Tiingo Power makes capped responses look like successful empty responses. Always check the body before parsing JSON.▾
When Tiingo throttles you, it returns 200 with a body that says 'You have exceeded your quota.' If you blindly parse JSON, you get a malformed-but-successful read and silent degradation. Sniff the body for cap markers first.
21.DuckDB has one writer per file. Always.▾
Two processes cannot write to the same .duckdb. The architecture must enforce a single-writer process per persistent store — anything else is a corruption story waiting to happen.
22.The watchlist schema is an undocumented cross-process contract.▾
When two languages talk to the same SQLite file, the schema is the wire format. Changing a column name in TypeScript without updating the Python reader is a silent break — there is no compiler that catches it.
23.ETFs do not have float shares. They have AUM.▾
Free-float metrics don't apply to ETFs because the unit is created and redeemed by APs against the underlying basket. Asking yfinance for SPY floatShares returns null — and that null is correct. Render the metric as N/A, not as a missing value.
24.Yahoo handles cookies + crumb tokens. yfinance handles Yahoo.▾
Yahoo's quoteSummary endpoint requires a consent cookie + a crumb token. Writing that dance from scratch is a maintenance trap. yfinance handles it; use the library.
25.atexit checkpoints are mandatory for DuckDB.▾
DuckDB's WAL is replayed on next open. If your process exits without a CHECKPOINT, recent inserts can be rolled back. Register an atexit handler that checkpoints and closes the connection. Not optional.
26.SEC concept tie-breakers must rank us-gaap Outstanding over dei.▾
When both dei:EntityCommonStockSharesOutstanding and us-gaap:CommonStockSharesOutstanding report the same (end, filed), prefer us-gaap. Foreign ADR filers (BABA, JD, BIDU, PDD, NIO) tag dei with the ADS-equivalent count and us-gaap with the ordinary count. Picking dei first gives you a 10x understatement.
27.The dev server cache desyncs without warning. Restart it.▾
Turbopack's cache can get into a state where every route returns 500 with a build-manifest ENOENT. There is no graceful recovery path — kill the process, wipe .next/dev, restart.
28.Vercel deploys on push. Verify the build status, then the live URL.▾
A 'pushed' commit is not a 'shipped' commit. Wait for the Vercel build status to flip to Ready, then curl the production URL, then declare done.
29.Trust but verify: an agent's summary describes intent, not outcome.▾
When a subagent reports 'I added X', read the diff. The summary is what the agent intended; the diff is what actually happened. These are not always the same.
30.The 33rd degree does not tolerate ALBINO BUGS.▾
A page that flashes white on mobile overscroll is a bug, not a quirk. The browser's default background must be painted by the document, not left to the operating system. Honor every pixel.
31.The source of truth is the tape.▾
Headlines are commentary. Filings are commentary. Analyst notes are commentary. The tape — the print — is the only thing that cannot lie. Read it first.
32.Every datum has a source.▾
A claim without a citation is an opinion. An opinion sized as a position is a gamble. The discipline is to render only what can be cited, and to size only what can be defended.
33.If it cannot be cited, it cannot be said.▾
The final maxim. Synthesis silence is preferable to synthesis fabrication. When the chunks do not support the claim, the model must hold its tongue. The 33rd degree.