Methodology
Terminology
Every table on AlphaBaseline is built from public SEC filings, and the words around those tables have precise meanings. This page defines the terms we use so a number always means the same thing wherever you see it. For how the numbers are produced, see the data pipeline and backtest methodology pages.
Filings and disclosure
Form 13F (13F-HR)
A quarterly report that institutional investment managers with at least $100 million in qualifying U.S. equity assets must file with the SEC. It lists their long positions in U.S.-listed stocks at the end of the quarter. Almost every holding on this site comes from a 13F-HR filing.
Amendment (13F-HR/A)
A corrected or updated 13F that a manager files after the original. When a manager amends a quarter, the amended holdings replace the original ones for that reporting period, so the figures you see reflect the latest disclosure.
Reporting date vs. filing date
The reporting date is the quarter-end the holdings describe (for example 31 December 2025); the filing date is the day the manager actually sent the report to the SEC, which can be weeks later. We assign every filing to the quarter of its reporting date, not its filing date.
Disclosure date
The date a filing becomes public. The copy-investor backtest treats this as the earliest day an outsider could have acted on the disclosed portfolio.
Period (quarter)
A single calendar quarter, written as a year and quarter such as 2025 Q4. All portfolio and activity views are scoped to one period at a time.
Form 4
A filing that corporate insiders — officers, directors, and holders of more than 10% of a company — must submit when they trade their own company’s stock. These power the insider activity page and are separate from 13F holdings.
Managers and portfolios
Focused (high-conviction) investor
A manager who concentrates capital in a small number of positions rather than spreading it thinly across hundreds. AlphaBaseline curates roughly 80 such investors instead of indexing every 13F filer, because their biggest bets carry a clear, readable signal.
Manager vs. fund
A manager is the person or firm making decisions; a fund is the legal entity that files. The two are tracked together as the business key because a manager can change filing entities over time while remaining the same investor.
Holding (position)
A single security a manager reported owning in a given quarter, including the share count and the reported dollar value.
Long equity
An ordinary share position the manager owns outright. 13F long-equity values exclude short positions, cash, and most bonds, so a manager’s true book is usually larger than its disclosed 13F equity.
Holder count
The number of tracked managers that held a particular stock in a quarter. A high holder count means the position is crowded among respected investors.
Aggregate (reported) value
The sum of the reported dollar values of a position across every manager that held it. It reflects what managers disclosed at quarter-end, not a live market price.
Concentration (top-five)
The share of a manager’s equity portfolio held in its five largest positions. Higher concentration means higher conviction in fewer ideas.
Combined portfolio
Every tracked manager’s holdings added together into one book, used to see what the group owns collectively and which stocks they crowd into.
Notional (put/call)
The face value of an options position, calculated from the contract size and strike. Notional is not the premium the manager paid and is not a stock position, so we report it separately from long equity to avoid overstating a portfolio.
CUSIP and ticker
A CUSIP is the nine-character identifier a 13F uses for a security; a ticker is the exchange symbol people recognise. We map each CUSIP to its current ticker so positions are searchable by symbol.
Quarter-over-quarter activity
On holdings and activity tables, each position is labelled by how it changed from the previous quarter. The label is computed by comparing the reported share counts of the two quarters.
New
The manager held none of the stock last quarter and opened a position this quarter.
Add
The manager already held the stock and increased the share count.
Reduce
The manager held the stock and decreased the share count without selling out entirely.
Exit
The manager held the stock last quarter and reported none of it this quarter.
Hold
The share count was unchanged from the previous quarter.
Backtest
The backtest measures what an outsider would have earned by mechanically copying a manager’s disclosed portfolio. The backtest methodology page carries the full math.
Copy-investor backtest
A simulation that buys a manager’s disclosed equity portfolio on the date the 13F becomes public, holds it until the next disclosure, then rebalances into the new portfolio. It answers what following the manager would actually have returned.
Leg
One disclosure-to-disclosure holding period for one position. Each leg is a single buy-and-hold that the backtest can price and audit on its own.
Rebalance
The act of switching from one quarter’s disclosed portfolio to the next when a new filing lands.
Weight renormalisation
Because options, bonds, and unpriced names are excluded, the remaining equity weights are rescaled to sum to 100% so the simulated portfolio is fully invested in the priceable equity slice.
Q, 1Y, 3Y returns
Q is the return of the most recently closed holding period; 1Y and 3Y are the compounded returns of the closed periods ending within the trailing one and three years. A period is suppressed when the strategy lacks enough priced history to fill the window.
3Y Top 5
The same three-year backtest, but each quarter counts only that quarter’s five largest priced positions. It answers whether the manager’s highest-conviction ideas alone beat the full portfolio.
Stale
A marker that a manager’s most recent expected quarterly filing has not yet been indexed, so the headline figures may lag the latest disclosure.
Pricing and data quality
Split adjustment
When a stock splits, historical prices are restated so a position’s return is not distorted by the share-count change rather than real performance.
Pricing coverage
The share of tracked positions for which we have market prices good enough to include in the backtest. Positions without coverage are left out of return calculations rather than guessed.
QA-certified quarter
A quarter whose served data has passed AlphaBaseline’s automated validation checks against the raw filings and independent sources, so its figures are trusted for headline claims.