# United States tariff line 3913.90.50.00: Other

> In the United States tariff, line 3913.90.50.00 covers natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms. The general (MFN) duty rate is 6.5%. It falls under HS subheading 3913.90 in heading 39.13 (chapter 39).

Source: https://border.bot/countries/united-states/hs-codes/3913905000
Last updated: 9 October 2026

[Countries](https://border.bot/countries) / [United States](https://border.bot/countries/united-states) / [Chapter 39](https://border.bot/countries/united-states/hs-codes/39) / [3913.90](https://border.bot/countries/united-states/hs-codes/391390) / [3913.90.50.00](https://border.bot/countries/united-states/hs-codes/3913905000)

## Key facts

- Tariff line: 3913.90.50.00
- Covers: Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms
- Duty (MFN): 6.5%
- Preferential rates: From free (17 programmes or origins)
- Additional duties: None recorded
- Restrictions: None recorded
- Tariff: [United States](https://border.bot/countries/united-states)
- HS subheading: [3913.90](https://border.bot/hs-codes/391390)

## What this line covers

In the United States tariff, line 3913.90.50.00 covers natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms.

Its legal text is “Other”, read under “Other”.

## How it is structured

It falls under HS subheading 3913.90 in heading 39.13 (chapter 39). The first six digits are the Harmonized System code; the 4 digits after them are added by the United States tariff.

- Chapter 39: Plastics and articles thereof
- Heading 39.13: Natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms
- Subheading 3913.90: Other
- Line 3913.90.50.00: Other

## Duty

The general (MFN) duty rate is 6.5%.

Duty-free entry applies to goods that qualify under 16 programmes, and to goods from a group of origins (origin group A*).

- Free: a group of origins (origin group A*) (A*)
- Free: United States-Australia Free Trade Agreement (AU)
- Free: United States-Bahrain Free Trade Agreement Implementation Act (BH)
- Free: United States-Chile Free Trade Agreement (CL)
- Free: United States-Colombia Trade Promotion Agreement Implementation Act (CO)
- Free: African Growth and Opportunity Act (D)
- Free: Caribbean Basin Economic Recovery Act (E)
- Free: United States-Israel Free Trade Area (IL)
- Free: United States-Jordan Free Trade Area Implementation Act (JO)
- Free: United States-Korea Free Trade Agreement Implementation Act (KR)
- Free: United States-Morocco Free Trade Agreement Implementation Act (MA)
- Free: United States-Oman Free Trade Agreement Implementation Act (OM)
- Free: Dominican Republic-Central America-United States Free Trade Agreement (P)
- Free: United States-Panama Trade Promotion Agreement Implementation Act (PA)
- Free: United States-Peru Trade Promotion Agreement Implementation Act (PE)
- Free: United States-Mexico-Canada Agreement (S)
- Free: United States-Singapore Free Trade Agreement (SG)

## In other countries

No other national tariff on border.bot has live lines under 3913.90 yet.

- [The Harmonized System text for 3913.90](https://border.bot/hs-codes/391390)

## Other lines under 3913.90

- [3913.90.10.00](https://border.bot/countries/united-states/hs-codes/3913901000) Chemical derivatives of natural rubber
- [3913.90.20.15](https://border.bot/countries/united-states/hs-codes/3913902015) Xanthan gum
- [3913.90.20.90](https://border.bot/countries/united-states/hs-codes/3913902090) Other

- Previous line: [3913.90.20.90](https://border.bot/countries/united-states/hs-codes/3913902090) Other
- Next line: [3914.00.20.00](https://border.bot/countries/united-states/hs-codes/3914002000) Cross-linked polyvinylbenzyltrimethylammonium chloride (Cholestyramine resin USP)

## Frequently asked questions

### What does tariff line 3913.90.50.00 cover in the United States tariff?

In the United States tariff, line 3913.90.50.00 covers natural polymers (for example, alginic acid) and modified natural polymers (for example, hardened proteins, chemical derivatives of natural rubber), not elsewhere specified or included, in primary forms.

### What is the general (MFN) duty on 3913.90.50.00 in the United States?

The general (MFN) duty rate is 6.5%.

### Which preferential rates apply to 3913.90.50.00?

Duty-free entry applies to goods that qualify under 16 programmes: the United States-Australia Free Trade Agreement, the United States-Bahrain Free Trade Agreement Implementation Act, the United States-Chile Free Trade Agreement, the United States-Colombia Trade Promotion Agreement Implementation Act, African Growth and Opportunity Act, Caribbean Basin Economic Recovery Act, the United States-Israel Free Trade Area, the United States-Jordan Free Trade Area Implementation Act, the United States-Korea Free Trade Agreement Implementation Act, the United States-Morocco Free Trade Agreement Implementation Act, the United States-Oman Free Trade Agreement Implementation Act, the Dominican Republic-Central America-United States Free Trade Agreement, the United States-Panama Trade Promotion Agreement Implementation Act, the United States-Peru Trade Promotion Agreement Implementation Act, the United States-Mexico-Canada Agreement and the United States-Singapore Free Trade Agreement, and to goods from a group of origins (origin group A*).

## Sources and updates

The tariff lines for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The duty rates for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

The trade programmes for the United States come from border.bot release 1 (edition 2026HTSRev21), read from the publisher’s files, and have been live since 9 October 2026.

This page was last updated on 9 October 2026.

Guidance from published tariff data, not a binding ruling. For a decision customs must follow, apply to the destination’s customs authority for a binding tariff ruling.

Official source files:

- https://hts.usitc.gov/reststop/exportList?from=0000000000&to=9999999999&format=CSV&styles=false

Machine-readable: https://border.bot/countries/united-states/hs-codes/3913905000.json