Every halal fund, ETF and robo-adviser in Britain rests on the same underlying machinery: a two-stage screen that decides which of the world's listed companies a Muslim can own. Understanding it takes ten minutes and permanently changes how you read a factsheet, because the screens explain both what these products hold and why they all look strangely similar. This is the machinery, explained for a UK audience.
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Test one: what the business does
The first screen removes companies whose core business is impermissible. The standard exclusion list, applied by both major index families used in UK products, covers alcohol, tobacco, pork products, conventional banking and insurance, gambling, weapons and adult entertainment. This is the intuitive half of screening and the least contested: a brewery is out regardless of how conservatively it is financed. Where methodologies differ is at the margins, such as hotels that serve alcohol or supermarkets with tobacco aisles, which is where revenue-percentage rules come in. Standard Life's Shariah pension fund factsheet, for instance, documents exclusion of companies deriving over 5% of revenue from restricted activities, a threshold construction common across the industry.
Test two: how the balance sheet is financed
The second screen is the one that surprises newcomers. A company with a perfectly halal product can fail screening because of its finances: too much interest-bearing debt, too much cash parked in interest-earning instruments, or too much income from interest. The MSCI Islamic Index Series, used by the iShares Islamic ETFs, applies AAOIFI-consistent 33% thresholds to these financial ratios. The Dow Jones Islamic Market methodology, used by the HSBC Islamic fund, applies its own ratio construction. The thresholds are scholarly pragmatism: a pure zero-interest rule would exclude virtually every listed company on earth, so the tradition tolerates a limited entanglement and requires purification of the residue.
Why different screens produce different funds
Because the ratio arithmetic differs, a large company can pass Dow Jones and fail MSCI, or the reverse. This is why ISWD and the HSBC fund, both marketed as global Islamic equity, hold meaningfully different portfolios: MSCI's stricter financial screens keep more old-economy names and cut some borderline mega-caps, while the Dow Jones Titans universe leans harder into large-cap technology. At 31 May 2026, technology hardware plus software exceeded 53% of the HSBC fund. Neither list is 'more Islamic' in any absolute sense; they encode different tolerances within the same juristic framework. Investors uncomfortable with permissive ratios can simply prefer the MSCI-screened products.
The purification step
Screening tolerates small impure income, typically up to 5% of a company's revenue, so a compliant portfolio still generates a sliver of income a Muslim should not keep. The remedy is purification: calculating that portion and giving it to charity. Index providers publish purification ratios per fund or index; managed platforms like Wahed calculate and donate it automatically, and Simply Ethical does the sums for clients annually. DIY investors own the job, and our dividend purification guide walks through the method. Purification is what makes the 33% tolerance defensible: the system is screen, tolerate, cleanse.
Screening a single stock yourself
- Check the business: does any meaningful revenue come from the exclusion list?
- Check the ratios: interest-bearing debt, interest-earning cash and impure income against your chosen methodology's thresholds, using the latest accounts.
- Remember ratios move: a compliant company can drift out of compliance after a debt-funded acquisition, so screening is periodic, not one-off.
- Log the impure income percentage for purification of dividends you receive.
This is exactly the work index providers industrialise, which is the practical argument for funds over stock-picking for most investors. Our halal stocks hub covers the single-stock route in more depth.
A worked example of the two tests
Run a hypothetical retailer through the machine. Business test: it sells groceries, including a tobacco counter contributing 2% of revenue. Under a 5%-threshold methodology the activity passes, with that 2% flagged as impure income. Financial test: the retailer carries debt from store expansion; if its interest-bearing debt sits below the methodology's 33% ratio threshold, it passes; if a leveraged acquisition pushed the ratio above, it fails regardless of the halal shelves. If it passes both, the stock enters the compliant universe, and an investor's dividends carry a 2% purification obligation. Every fund in our best funds guide is this exercise industrialised across thousands of companies, quarterly, with scholars auditing the process.
Why financials dominate the exclusion list
Newcomers expect breweries and casinos to dominate screening; in practice, conventional finance is the largest single exclusion by market weight. Banks and insurers earn from interest as their core business, no ratio test can rescue them, and they constitute a huge slice of every major index. Removing them reshapes the compliant universe more than every other exclusion combined, and explains the sector fingerprints of Islamic funds: overweight technology and healthcare, where cash-rich balance sheets pass ratio tests easily, underweight everything that lives on leverage. The concentration analysis traces where that leads portfolios.
Frequently asked questions
Who decides these rules?
Scholarly bodies and the Shariah boards of index providers and fund managers, working within frameworks like AAOIFI's standards. UK-available products name their scholars: HSBC's three-member Global Shariah Supervisory Committee, the four-scholar Amanie Advisors panel in the iShares prospectus, Shariyah Review Bureau at Wahed. The named accountability is a feature; anonymous compliance claims deserve suspicion.
Is buying shares gambling?
Mainstream scholarship distinguishes share ownership, a real stake in a real business's profits and losses, from maysir, wagering on pure chance. Day-trading and speculation sit closer to the line and attract more scholarly criticism; long-term ownership of screened businesses is broadly accepted.
Do I need to purify capital gains too?
The dominant practice purifies the impure income portion, applied via published purification ratios, with methodologies differing on the exact base. Accumulating funds fold income into the price, which is why their disclosures matter. Where scholarly opinions differ, pick a consistent method and follow it; inconsistency is the only indefensible approach.
Can a stock be halal one year and haram the next?
Yes, through the financial ratios. Index funds handle this by reconstituting at review dates, selling names that fall out of compliance. DIY stock-pickers must re-screen holdings periodically, one more quiet argument for the fund route covered in our best funds guide.
Are there halal stock screening apps?
Several apps screen individual tickers against stated methodologies, useful as a first pass for stock-pickers. Treat them as tools rather than fatwas: methodologies differ between apps exactly as between MSCI and Dow Jones, and a ticker's status can lag a balance-sheet change. For portfolio-scale investing, index-level screening with scholar oversight remains the robust route.
Does screening guarantee a company is ethical?
No, and precision here prevents disappointment. Screening tests activity categories and financial ratios; it does not audit labour practices, environmental records or governance quality, dimensions secular ESG frameworks attempt and Shariah methodology does not address. A compliant company can still behave badly within permissible industries. Investors who want both filters stacked can pursue the hybrid instruments discussed in our ESG and halal comparison, accepting the narrower universe that results.
Compare providers in your state
See side-by-side comparisons of Shariah-compliant products, or let our matcher recommend the best options for your situation.
The screening habit, condensed
Screen before you buy, using a screening tool or the index methodologies this article walked through; record the date and result. Re-screen holdings annually, because balance sheets drift across thresholds without any announcement. Purify dividends per our purification guide, and sell within your method's grace period when a holding fails. Four habits, one calendar entry, and the DIY route becomes as disciplined as any certified fund. Figures and methodology details verified August 6, 2026.