Three layers. First, the universe wide sector mix and how dominant software has become. Second, per BDC concentration scoring using the Herfindahl Hirschman Index, the antitrust regulator's standard for diversification. Third, a fund by sector heat map that lets you find every BDC with above market exposure to any sector that matters to you.
Single sector concentration risk. Could be deliberate (specialist lender like a healthcare or tech focused BDC) or accidental (residual position drift). Calculated as Σ(weight²) × 10,000 over fair value weights.
Lowest HHI scores in the universe. These funds spread fair value most evenly across sectors. Wider diversification typically associates with more stable NAV per share (Claremont Colleges study).
The Herfindahl Hirschman Index measures portfolio concentration. For each BDC, take the share of each sector in the portfolio, square it, sum the squares, then multiply by 10,000. A fund 100% in one sector scores 10,000; a fund split evenly across 10 sectors scores 1,000.
The US Department of Justice uses HHI to evaluate market concentration in antitrust reviews. We apply their thresholds directly: < 1,500 low concentration, 1,500–2,500 moderate, > 2,500 high. These thresholds are not arbitrary; they map to outcomes the regulator has empirically associated with market stress.
We also report an adjusted HHI per the S&P methodology, dividing raw HHI by the HHI of an equal weight portfolio with the same number of sectors. That removes the bias toward low scores in funds that simply report more sector buckets.
BDCs file sector data with no standard taxonomy. ARCC uses Moody's industry categories, Blackstone uses GICS, Blue Owl uses its own internal grouping. We mapped 614 unique raw sector labels into 16 canonical buckets using keyword rules. About 2.4% of fair value lands in the residual "Other" bucket; this is shown honestly rather than force fit.
Some BDCs file sector data hierarchically · a top level total like "Senior Loans" plus a per sector breakdown underneath, which causes weights to sum to more than 100% if both levels are extracted. Where we detect this, we rebase each fund's weights to sum to 100% so the relative shape is correct, and flag funds where the rebasing was material so a reviewer can audit.
Stress thresholds drawn on the heat map: 25% software exposure per Morgan Stanley's red line (March 2026 piece), 35% in any single sector per the general cycle warning band, and top three sectors above 60% per the concentration warning. A cell outlined in amber means the BDC is above the relevant threshold for that sector; red means above the critical level.
Latest SOI snapshot per fund. The freshest data is from Q1 2026 10-Q filings; some non traded BDCs file later. Click any cell to drill into the underlying borrower list (coming in a future iteration).