ShariahSignal

Halal Equity Screener & Intelligence
Quantitative Whitepaper & Formulas

Shariah Screening Methodology & Mathematical Derivations

An exhaustive technical breakdown of equity screening jurisprudence, financial ratio ceilings, denominator mechanics, dividend purification formulas, and quantitative health scoring across international benchmarks.

1. Overview of the 2-Tier Screening Architecture

In Islamic jurisprudence (Fiqh al-Mu'amalat), equity ownership in publicly traded corporations is governed under the legal contract of fractional partnership (Musharakah or Qirad). Because modern public corporations rarely operate in 100% debt-free or interest-free environments, contemporary scholars have established a rigorous two-tier screening architecture based on the legal maxim of Umum al-Balwa (widespread economic necessity).

ShariahSignal executes this two-tier screening process deterministically across all monitored equities:

Deterministic Guarantee: ShariahSignal does not employ subjective human discretion or black-box machine learning predictions to determine compliance status. Every single status (Compliant, Doubtful, or Non-Compliant) is the direct output of verifiable mathematical equations applied to audited balance sheet lines.

2. Core Mathematical Screening Formulas

Under AAOIFI Standard No. 21 (Articles 3/1 to 3/4), the four mandatory quantitative screening ratios are formulated as follows:

Ratio 1: Interest-Bearing Debt Ceiling
Debt Ratio = (Short-Term Debt + Long-Term Debt) / Total Assets ≤ 30.0%
Total interest-bearing liabilities must not exceed 30% of Total Assets (or 36-Month Average Market Capitalization). Prevents investors from financing businesses heavily leveraged by conventional usury (Riba).
Ratio 2: Cash & Interest-Bearing Securities Ceiling
Cash Ratio = (Cash & Equivalents + Fixed Deposits + Marketable Securities) / Total Assets ≤ 30.0%
Cash and interest-earning bank deposits must not exceed 30% of Total Assets. In Islamic law, trading shares of a company whose assets are predominantly cash constitutes trading money-for-money (Sarf), requiring exact par-value exchange.
Ratio 3: Accounts Receivable Ceiling
Receivables Ratio = Trade Accounts Receivable / Total Assets ≤ 67.0%
Trade credit extended to customers must not exceed 67% of Total Assets under AAOIFI (or 33% under DJIM/FTSE). Under the principle of Bay' al-Dayn, trading shares composed primarily of debt receivables at a market premium is strictly prohibited.
Ratio 4: Non-Permissible Income & Purification Factor
Impure Revenue Ratio = (Interest Income + Non-Permissible Operating Income) / Total Gross Revenue ≤ 5.0%
Incidental impure income must remain below 5% of gross revenues. Furthermore, this exact percentage must be extracted from all dividend distributions and donated to charity without spiritual reward expectation.

3. The Denominator Debate: Total Assets vs. Market Capitalization

One of the most consequential divergences in contemporary Islamic finance is the choice of denominator when calculating financial ratios:

Standard Primary Denominator Debt Limit Cash Limit Receivables Limit
AAOIFI Standard 21 Total Assets (Book Value) or 36M Avg Market Cap ≤ 30.0% ≤ 30.0% ≤ 67.0%
DJIM (Dow Jones) Trailing 24-Month Average Market Capitalization ≤ 33.0% ≤ 33.0% ≤ 33.0%
FTSE Shariah Total Assets ≤ 33.3% ≤ 33.3% ≤ 50.0%
MSCI Islamic Total Assets ≤ 33.3% ≤ 33.3% ≤ 33.3%
SC Malaysia SAC Total Assets & 5% / 20% Activity Benchmark ≤ 33.0% ≤ 33.0% —

Why the Choice Matters

Market Capitalization Denominators (DJIM): Reflect the current enterprise market valuation. However, during severe bear market crashes, a company's market cap can decline by 50% without the company taking on a single dollar of new debt. This triggers artificial "false-positive" non-compliance flags purely due to market volatility.

Total Assets Denominators (AAOIFI & MSCI): Anchor screening to the physical and accounting balance sheet assets. This provides immense structural stability during equity panics. ShariahSignal allows users to toggle between both standards or view side-by-side compliance audits.

4. Mathematical Derivation of Dividend Purification

When an otherwise compliant corporation parks operating surplus cash in short-term bank deposits, it earns interest income. Because this tainted income forms part of total company earnings, any dividend distributed to shareholders contains a pro-rata fraction of impermissible wealth.

The mandatory purification formula is derived as:

Purification Amount Equation
Purification Due ($) = Dividend Received ($) × [ Impure Non-Operating Income / Total Gross Revenue ]
Example: If you receive $1,000 in dividends from a company where interest income represents 1.2% of total gross revenue, your purification obligation is $1,000 × 0.012 = $12.00.

Capital Gains Treatment: Under the overwhelming consensus of international scholars (including AAOIFI and the Islamic Fiqh Academy), capital gains realized from selling shares at a market premium do NOT require purification, provided the company was Shariah-compliant throughout the holding period. Capital gains reflect changes in enterprise valuation and market liquidity, not interest payments.

5. Prohibited Business Activity Criteria

Before any balance sheet calculations take place, ShariahSignal filters out companies engaged in prohibited commercial sectors. A company is automatically classified as Non-Compliant if more than 5% of its gross revenue originates from: