Methodology

The index universe covers unlisted (non-traded) business development companies (BDCs) registered with the SEC. These are closed-end funds that have elected BDC status under the Investment Company Act and invest primarily in private credit and equity.

Discovery

Unlisted BDCs are identified through three independent SEC data sources:

1. N-54A/N-54C elections -- BDCs that have elected or withdrawn BDC status with the SEC
2. 814- file numbers -- CIKs with Investment Company Act file numbers in the 814 series
3. SEC BDC data set -- CIKs appearing in the SEC's structured BDC data sets

Exclusions

Listed (publicly traded) BDCs are excluded. The unlisted BDC reference list is cross-validated against third-party sources. Consumer and marketplace lending vehicles with opaque individual loan IDs are excluded from index-level outputs.

All data is sourced from SEC EDGAR. No voluntary manager surveys, no proprietary feeds. This eliminates selection bias and ensures complete coverage of the filing universe.

BDC XBRL (10-K/10-Q)

Business Development Companies file annual (10-K) and quarterly (10-Q) reports that include a Schedule of Investments in structured XBRL format. The SEC required inline XBRL tagging for BDC investment schedules starting in 2022-2023. Each position is tagged with fair value, cost, interest rate, maturity, and other attributes using a typed dimension (investmentIdentifierAxis).

Extraction

XBRL instance documents are downloaded and parsed. A concept mapping layer handles variations in XBRL taxonomies across filers. Rate harmonization converts BDC rates from decimal to percentage form. Per-CIK wrappers handle filer-specific XBRL variations.

Two indices are published, each tracking a distinct segment of the private markets:

Position Matching

To compute returns, the same position must be linked across consecutive quarters. A three-tier matching cascade is used:

1. Tier A: Within-filing comparatives -- BDC XBRL filings contain both current and prior-period facts under the same investmentIdentifierAxis value.
2. Tier B: Exact name matching -- Positions matched by exact issuer_name within the same CIK across adjacent quarters.
3. Tier C/D: Normalized and fuzzy matching -- Fallback matching using name normalization and Jaro-Winkler similarity with fair value proximity guards.

Total return for each position is decomposed into components, following the convention of public credit indices:

Capital Return (Price)

Per-unit price return isolates price changes from quantity changes. For loans: price = fair_value / principal_amount. For equity: price = fair_value / shares_held, with fallback to fair_value / cost. This prevents amortizing loans from being penalized and new purchases from inflating returns.

Income Return

Estimated coupon accrual based on a three-tier rate imputation: (1) direct interest_rate from the filing, (2) basis_spread plus implied SOFR from peer filers, (3) same-filer median rate.

Aggregation

Index-level returns are fair-value-weighted averages across all constituents. Equal-weighted returns are also published. Index levels are chain-linked from a base of 100. A minimum of 10 constituents per quarter is required for a valid observation.

Beyond index returns, the platform publishes fund-level analytics and portfolio characteristics:

• Portfolio characteristics -- Weighted average coupon, spread, and maturity with coverage disclosure
• Structural composition -- Lien position, rate type, and asset class breakdowns
• Manager concentration -- AUM share by adviser
• Fund-level performance -- NAV returns, distribution rates, leverage ratios
• Credit risk indicators -- PIK exposure, non-accrual rates, default flags where disclosed

All analytics are derived from the same mandatory filing data. Coverage gaps are disclosed inline (e.g., "86% coverage" next to weighted average coupon).

• Coverage starts ~2022 -- BDC XBRL tagging was phased in by the SEC starting in 2022. Pre-2022 filings are unstructured HTML.
• Quarterly frequency -- Unlike daily public market indices, these indices update quarterly due to the filing cadence.
• Fair value estimation -- Reported fair values reflect fund-level mark-to-model estimates, not market transaction prices.
• Survivorship bias -- Funds that de-register or stop filing exit the index. Historical returns include only active filers.
• Incomplete field coverage -- Portfolio characteristics are based on positions where the filer disclosed the relevant data. Coverage rates are disclosed alongside each metric.
• No leverage adjustment -- Returns reflect gross portfolio performance, not fund-level returns which may include leverage effects.