FinToolSuite

Portfolio Loan Calculator

Updated April 17, 2026 · Mortgage · Educational use only ·

Loan amount available against portfolio value.

Calculate the maximum loan available against a securities portfolio based on margin rate and portfolio value. Free and runs in your browser.

What this tool does

Enter portfolio value and margin rate. The tool shows maximum loan available and margin call threshold.


Enter Values

Value is unusually high — please double-check

Formula Used
Total portfolio
Allowed borrow %

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Calculations, display, or translation — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

Portfolio loans (securities-backed loans) typically let you borrow 50-70% of portfolio value. 500,000 portfolio at 50% margin = 250,000 loan available. Margin call triggers when portfolio drops below maintenance level, typically 30-35%. Cheaper than unsecured credit but the collateral is market-exposed. Liquidation risk in downturns is the structural concern.

Run it with sensible defaults

Using portfolio value of 500,000, margin rate of 50%, maintenance percentage of 35%, the calculation works out to 250,000.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Portfolio Value, Margin Rate, and Maintenance Percentage — do not pull with equal force. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

How the math works

Portfolio × margin rate = max loan. Margin call threshold = max loan / maintenance percentage. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

What the headline rate hides

Lenders quote a rate; what you pay is a blend of that rate, fees, insurance, and any early-repayment penalty built into the product. The figure here isolates the core interest cost so you can compare like-for-like across deals — then add the other costs separately before signing anything.

What this doesn't capture

The figure excludes arrangement fees, valuation costs, legal fees, insurance, and any early-repayment charges — those can add several thousand to the headline cost. Rate changes at renewal for fixed-term deals will shift the picture further. Use this for the core interest/principal math and add the other costs on top.

Example Scenario

Portfolio loan produces a loan amount based on the inputs provided.

Inputs

Portfolio Value:500,000 £
Margin Rate:50
Maintenance Percentage:35
Expected Result£250,000.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Portfolio × margin rate = max loan. Margin call threshold = max loan / maintenance percentage.

Frequently Asked Questions

Is this better than a mortgage?
Usually lower rate than unsecured credit; competitive with mortgages for high-net-worth clients. But the collateral is volatile — liquidation risk is real.
What triggers margin call?
Portfolio dropping below the maintenance threshold. If loan is 50% of portfolio and maintenance is 35%, a 30% market drop triggers call.
Tax implications?
Borrowing doesn't trigger capital gains (no sale). Interest may be deductible if used for investment. Forced liquidation during margin call does trigger gains.
Best use cases?
Bridging liquidity needs, tax-efficient short-term financing, flexible cash without selling investments. Not for long-term lifestyle funding.

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