---
title: "What is the currency margin?"
description: "This article explains the currency margin mechanism of Longbridge Securities for currency borrowing trades.If you use currency borrowing trades (such as holding Hong Kong dollars to buy US stocks), due to the risk of exchange rate fluctuations, Longbridge will charge a certain percentage of currency margin.Example:When you deposit HKD 20,000 and purchase US stocks with a market value of USD 2,000, the US stock market"
slug: "1ddrdj"
locale: "en"
region: "hk"
region_label: "Hong Kong"
url: "https://longbridge.com/hk/en/support/topics/marginfinancing/1ddrdj.md"
updated_at: "2025-10-10T07:36:07.000Z"
category: "marginfinancing"
category_title: "Margin financing"
references:
  related:
    - title: "Guide to Longbridge Integrated Account"
      url: "https://longbridge.com/hk/en/support/topics/marginfinancing/3aysfh8.md"
    - title: "Margin Call Rules"
      url: "https://longbridge.com/hk/en/support/topics/marginfinancing/2u2kyg0.md"
    - title: "Margin Financing Related FAQs"
      url: "https://longbridge.com/hk/en/support/topics/marginfinancing/2npbyr3.md"
    - title: "Account Risk Control Rules"
      url: "https://longbridge.com/hk/en/support/topics/marginfinancing/169xolr.md"
    - title: "How to check if a stock supports margin trading?"
      url: "https://longbridge.com/hk/en/support/topics/marginfinancing/f3rni3x.md"
---

# What is the currency margin?

[Table of Contents](https://longbridge.com/hk/en/support/toc.md)

This article explains the currency margin mechanism of Longbridge Securities for currency borrowing trades.

If you use currency borrowing trades (such as holding Hong Kong dollars to buy US stocks), due to the risk of exchange rate fluctuations, Longbridge will charge a certain percentage of currency margin.

**Example:**

When you deposit HKD 20,000 and purchase US stocks with a market value of USD 2,000, the US stock market value subsequently falls to USD 1,900. Although the overall net asset value of the account is approximately HKD 19,220 (calculated at an exchange rate of 7.8), the US dollar is insolvent and a currency margin of USD 4 will be charged for each USD 100.

**The currency margin is counted in buying power, withdrawals, and margin calls.**

HKD Balance

HKD 20,000

USD Balance

USD -2,000

Market value of holdings

USD 1,900

Net worth of HKD asset

HKD 20,000

Net worth of USD asset

USD -100

Currency Margin

USD 100 \* 0.04 = USD 4

**The following are the currency margin ratios for two currencies:**

Currency

Currency Margin

USD

4%

HKD

4%

**Key takeaways:**

-   **Triggering condition:** Liabilities appear in the net asset worth of the borrowing currency.
-   **Calculation rules:**
    -   Margin = Liability amount × 4% (USD/HKD flat rate)
    -   Included in buying power, withdrawals, and margin call checks

**Disclosure**

*This article is for reference only and does not constitute any investment advice.*

---

> **Disclaimer**: This article is for reference only and does not constitute any investment advice. Content provided by [Longbridge](https://longbridge.com).