Methodology
Every figure on this site follows a published rule. Calculations are implemented in tested application code (not generated by a language model), versioned, and each computed value stores the dates of its inputs.
Coverage and fund universe
How funds enter the database, how they are verified, and what is deliberately excluded.
Premium/discount and Z-scores
The signed calculation, contemporaneity rules, window definitions and sample gates.
Distribution rates and classification
Regular vs special, annualisation, trailing yields, and change detection.
Performance calculations
Four return series, reinvestment convention, annualisation and corporate-action handling.
Risk statistics
Volatility, drawdown, Sharpe, Sortino, beta and correlation — with their specifications.
Ranking methodology
Universe, eligibility, snapshot consistency, tie-breakers and refresh schedule for the twelve lists.
Holdings, allocations and overlap
N-PORT source, weight basis, allocation roll-ups and the overlap formula.
Fees, leverage and coverage
Where the numbers come from and the denominators behind each percentage.
Data freshness and provenance
Every value carries its own date, source and retrieval time; how we label reported, calculated, estimated and stale.
Ranking-specific rules
- Highest Distribution Yield — Trailing 12-month yield = actual distributions with ex-dates in the past 12 months ÷ latest market price; the default includes special distributions and flags them.
- Best Historical Performance — Total return reinvests distributions at the series value on the ex-date; periods over one year are annualised.
- Largest Discounts to NAV — Premium/discount uses the closing price and NAV published for the same date (contemporaneous).
- Largest Premiums to NAV — Same contemporaneous calculation and freshness rule as the discount list.
- Lowest Discount/Premium Z-Scores — Z = (current premium/discount − window mean) ÷ window sample standard deviation, on daily contemporaneous pairs.
- Largest Funds — Common net assets are the latest reported figure from SEC XBRL where available, otherwise calculated from N-PORT position values ÷ weights (labelled on each fund page).
- Most Actively Traded Funds — Dollar volume = Σ (close × volume) ÷ trading days over the last 63 end-of-day bars (minimum 20 bars).
- Lowest Expenses — Source: Inline XBRL fee-table facts from N-2 registration statements and annual reports (cef:TotalAnnualExpensesPercent and components).
- Trending CEFs — Counts fund-page views over the trailing 7 days, excluding known crawlers and monitoring agents by user agent.
- Highest Reported NII Coverage — Coverage is restricted to income strategies (taxable and municipal fixed income) with a reported figure from the last 18 months.
- Best Historical Risk-Adjusted Returns — Daily total-return observations over 3 years, minimum 500; annualised with √252.
- Lowest Historical Volatility — Volatility = sample SD of daily total returns × √252; consecutive observations more than 7 days apart are skipped to avoid sparse-series artefacts.
Calculation version: 2026.09.23-1. See also data sources & licensing and the corrections policy.