Halal compliance, sector by sector

Healthcare leads at roughly 40 percent of stocks passing the AAOIFI Standard 21 screen, followed by Energy at about 50 percent on a narrower universe basis. Information Technology, Industrials, and Materials cluster in the 30-35 percent range. The structural reason is straightforward: these sectors host the largest population of operating businesses whose primary activity is not on the AAOIFI exclusion list and whose capital structures tend to stay below the 30 percent debt ratio threshold.

Conventional commercial banks earn the majority of their income from interest on loans, and AAOIFI Standard 21 excludes interest-bearing income structurally. Insurance companies are excluded because conventional insurance is built on premiums-and-claims structures whose underlying reserves are invested in interest-bearing securities. The only common Financials sub-sectors that pass are payment networks like Visa and Mastercard, certain financial-data and ratings businesses, and a small number of Islamic banks listed in Gulf and Southeast Asian markets.

The S&P 500 has a Financials weight around 13 percent and a Technology weight around 30 percent. The halal-compliant universe has effectively zero Financials weight (only a handful of Islamic banks pass, and they are not in the S&P 500) and a much higher Technology weight, often above 40 percent. Energy and Healthcare are also overrepresented relative to broad indices. Communication Services and Consumer Discretionary are underrepresented because of media-content and gambling exclusions respectively.

It is a feature, not a bug, of Shariah-compliant investing - but it is a real consideration. A halal portfolio that mirrors the compliant universe will run heavier in Tech, Healthcare, and Energy and lighter in Financials, Utilities, and Consumer Discretionary than a broad index. The investor has two reasonable responses: accept the structural tilt (and the corresponding factor exposure) as the natural outcome of the screen, or actively balance within the compliant universe by capping the Tech allocation and over-weighting the smaller compliant sectors. invest-like exposes per-sector compliance counts so this decision can be made transparently.

Utilities are the highest-leverage sector in the S&P 500 universe. Regulated electric, gas, and water utilities are funded with large amounts of long-term debt because they own multi-decade fixed assets and their cash flows are stable enough to service that debt. The debt ratio test is the binding constraint - a typical regulated utility runs a debt-to-market-cap ratio above 30 percent, sometimes well above. The primary-business test is rarely an issue for utilities; it is the leverage that excludes them.

Biotech is a mixed case. Most pharmaceutical companies (large-cap and mid-cap) pass on both the primary-business and debt ratio tests because their products are health-related and their capital structures rely heavily on equity rather than debt. Smaller-cap biotech, especially pre-revenue research-stage names, often fail test 4 (liquid-assets ratio) because most of the market cap consists of cash raised from equity offerings that has not yet been deployed. The overall Healthcare sector pass rate of about 40 percent is the weighted average across these two regimes.

Real estate investment trusts split into two categories. Equity REITs - those that own and operate physical properties - can pass the screen if their property mix is Shariah-compliant (no concentration in alcohol-serving venues, gambling properties, or conventional bank branch portfolios) and their leverage stays below 30 percent. Mortgage REITs - those that hold pools of interest-bearing mortgages - are excluded structurally under the primary-business test because their income is riba. About 25 percent of the broader Real Estate sector passes, dominated by industrial, residential, and healthcare equity REITs.