The most overlooked rule in halal investing
If you follow Mufti Taqi Usmani — and millions of Muslim investors do — there's a screening rule in his published work that almost no halal-investing app implements.
It's called the illiquid-asset floor. It's been part of his methodology since the 1980s. And ignoring it can produce halal verdicts on stocks that, under his rulings, are actually not permissible.
This post explains the rule, the underlying logic, and what it changes for a real portfolio.
What the rule says
In An Introduction to Islamic Finance and in subsequent published guidance, Mufti Taqi Usmani has argued that for a stock to be permissible:
The total illiquid (tangible) assets of the company should constitute no less than 20% of its total assets.
That's it. One ratio, one threshold. But it's a rule that AAOIFI's Shariah Standard No. 21 — the basis of most halal-investing screens today — doesn't include.
What "illiquid" means here
In financial-accounting terms: anything on the balance sheet that isn't cash, receivables, marketable securities, or intangibles. Concretely:
- Property, plant, and equipment (manufacturing, real estate, hardware)
- Inventory (physical goods awaiting sale)
- Vehicles, machinery, infrastructure
- Land and buildings owned outright
- Capitalized costs of physical infrastructure
Specifically not illiquid:
- Cash and cash equivalents
- Money-market funds, treasury bills, commercial paper
- Receivables (money owed by customers)
- Goodwill, trademarks, patents (intangibles)
- Software, IP, brand value
For a manufacturing company like Toyota or Tesla, illiquid assets often exceed 50% of the balance sheet. For a pure software company like Adobe or Salesforce, they can drop below 20%.
Why this matters religiously
The underlying logic flows from a classical principle in Islamic finance. Trading shares is, in essence, trading partial ownership in a company. A company that is mostly cash + intangibles is, in commercial substance, trading paper for paper — a transaction that begins to resemble what Islamic jurisprudence calls bai' al-kali bi-l-kali (the sale of one debt for another), or more broadly approaches the impermissible category of speculative trading divorced from real economic activity.
A company with substantial tangible assets — factories, warehouses, equipment, inventory — represents real economic substance. Trading its shares is, in commercial substance, trading a stake in something that does something tangible.
The 20% threshold is Mufti Taqi's published line for "substantial enough." It's not arbitrary — it draws on the classical jurisprudential principle that a small admixture of impermissibility does not necessarily invalidate a transaction, but a dominant proportion does.
A worked example
Let's compare two real companies side-by-side under both AAOIFI and Mufti Taqi's screens.
Tesla, Inc. (TSLA):
| Ratio | Value | AAOIFI | Mufti Taqi |
|---|---|---|---|
| Interest income / revenue | 1.1% | ≤ 5% ✓ | ≤ 5% ✓ |
| Debt / market cap | 1.0% | ≤ 30% ✓ | ≤ 30% ✓ |
| Cash+sec / market cap | 3.5% | ≤ 30% ✓ | ≤ 30% ✓ |
| Illiquid assets / total assets | 52% | (not screened) | ≥ 20% ✓ |
Tesla is hardware: manufacturing plants, vehicles, batteries, inventory. 52% illiquid. Passes both standards.
Netflix, Inc. (NFLX):
| Ratio | Value | AAOIFI | Mufti Taqi |
|---|---|---|---|
| Interest income / revenue | 1.6% | ≤ 5% ✓ | ≤ 5% ✓ |
| Debt / market cap | 5.1% | ≤ 30% ✓ | ≤ 30% ✓ |
| Cash+sec / market cap | 2.3% | ≤ 30% ✓ | ≤ 30% ✓ |
| Illiquid assets / total assets | 14% | (not screened) | ≥ 20% ✗ |
Netflix is a content business — most of its balance sheet is licensed content assets (intangibles) and cash. Passes AAOIFI, fails Mufti Taqi.
The same logic applies to many beloved tech stocks: Amazon, Meta, NVIDIA, Salesforce, Adobe. All pass AAOIFI's screen. All fall below Mufti Taqi's illiquid-asset floor.
The portfolio implications
If you've been screening your portfolio against the default AAOIFI standard (which is what Zoya, Musaffa, Islamicly, and most halal robo-advisors use), and if you follow Mufti Taqi Usmani's published methodology, your portfolio may include holdings that you didn't realize were impermissible under his rules.
This is not an indictment of those apps. They made a reasonable product decision — pick the most-followed single standard and ship. But it's the gap Mizan was built to close.
How Mizan handles this
Mizan ships with six scholar profiles, and Mufti Taqi Usmani's profile is one of them. When you select it:
- The illiquid-asset floor is computed and displayed for every stock you screen.
- Stocks that pass AAOIFI but fail the illiquid floor are clearly marked FAIL under Mufti Taqi's profile, with the specific ratio highlighted.
- Capital gains purification (also part of his methodology) is calculated automatically in the Purification page.
No black-box score. No "trust us." You see the exact ratio, the exact threshold, and the exact reason for the verdict.
A note on practical guidance
For specific portfolio decisions, particularly when you have an existing position that's borderline, the right move is to consult a qualified scholar directly — your local imam, a member of your community's scholarly council, or a scholar whose rulings you follow.
Mizan provides scholarly opinions based on published methodologies. It does not provide individualized advice. The two are different and complementary.
Try Mizan with Mufti Taqi's profile
Open mizan.app, select the Mufti Taqi Usmani profile, and search any ticker. The illiquid-asset breakdown is displayed inline.
If you've been relying on a default halal screen and you follow Mufti Taqi, the first few searches may surprise you. That's the point.
Sources: Mufti Muhammad Taqi Usmani, "An Introduction to Islamic Finance," Maktaba Ma'ariful Quran (2002). AAOIFI Shariah Standard No. 21, Accounting and Auditing Organization for Islamic Financial Institutions. Financial figures sourced from public filings via Financial Modeling Prep, May 2026.