About PlainIndex

Most index-fund research sits behind a paywall, alongside ratings influenced by the issuers being rated. PlainIndex publishes the methodology in full, computes scores from public regulatory data, and keeps the affiliate side of the business strictly separated from anything that touches a fund's score.

How scores are computed

Every score on this site is a deterministic function of public data — expense ratios from fund prospectuses, holdings from SEC EDGAR N-PORT filings, AUM and yield from yfinance. The exact formulas, thresholds, and per-category numbers live on the methodology page — enough detail that any score can be replayed by hand from the raw inputs. If you can't replay our number, that's a bug — report it.

Where the data comes from

• SEC EDGAR Form N-PORT — every registered fund files monthly with the SEC. Only the third-month-of-quarter filing is publicly disclosed (with a 60-day lag); the other two months are kept confidential. Free where available.
• yfinance — Yahoo Finance's public data feed for daily prices, dividends, expense ratios, AUM, and TTM yield.
• Curated baseline — issuer, category, and benchmark mapping per fund, maintained in the repo. Preserves accurate fund metadata when scraped fields are missing.

We don't license data from any provider whose business depends on fund issuers paying for placement, ratings, or distribution access. That rules out Morningstar Direct, CRSP, and the major paid-research databases — the categorical wedge of this site is that any analyst at any cost level can audit the inputs.

Refresh cadence

• Daily — closing prices, AUM, TTM yield, expense ratios. Runs after US market close on weekdays. Leaderboards re-rank automatically.
• Monthly — N-PORT holdings re-pull. Drives pair-overlap and per-fund concentration sub-scores. Runs the 5th of each month after SEC EDGAR publishes the new filings.
• Annual — manual review of expense-ratio drift, category mappings, and methodology weights. Methodology version bumps are versioned and documented on the methodology page.

Catalog last refreshed 2026-06-08 · 408 funds tracked · methodology v0.5.0.

How it's funded

Brokerage affiliate links. PlainIndex receives a one-time referral fee when a reader opens a Fidelity account through the “Open at Fidelity” link on a per-ETF page. Affiliate relationships have no influence on any fund's score — methodology weights and thresholds are set before any affiliate ranking is computed and are versioned on the methodology page. Every affiliate link uses rel="nofollow sponsored" so search engines don't count it as an organic endorsement.

We don't run display advertising. We don't sell email lists; we don't have an email list. We don't accept payment from issuers for placement, ratings, or distribution. The affiliate-link disclosure is the entire commercial side of the operation.

Tracking and privacy

No third-party analytics tags, no advertising pixels, no cross-site cookies. Cloudflare web analytics runs at the edge and counts page views by URL — no individual visitor profile, no fingerprinting. You can browse anonymously and we don't know who you are.

Found a bug?

If a score on this site doesn't match what the methodology page says it should be, that's a bug. Email [email protected] with the ticker and what you expected — include the score you read, the score you calculated, and the input numbers you used so we can reproduce the discrepancy quickly.