ISO 4217 assigns one code per country, and the first two letters come from the country code. Yemen has one entry, YER. Since 2016 it has had two bodies acting as its central bank, and since a December 2019 circular the notes issued after 2016 are prohibited in the north.
A currency code identifies a country, not the body that prints the money. ISO 4217 gives Yemen one entry, YER, and that entry has not changed while the country has come to have two issuing authorities and two note series that are not accepted for each other. The gap between the code and the money is now visible in the statistics themselves.
Key Takeaways
- The first two letters of a currency code come from the country code, so the code follows the country rather than the issuer.
- Yemen has had two bodies acting as its central bank since 2016, one in Aden and one in Sana'a.
- A circular issued in Sana'a in December 2019 prohibited notes printed after September 2016 in the area it controls.
- The World Bank publishes two exchange rate rows for Yemen in one table, and ACAPS maintains two trackers.
- The code did not divide, and the standard has no mechanism by which it could.
What a three-letter currency code identifies
A country, mostly.
ISO sets out the construction plainly. The alphabetic code is built on ISO 3166, the standard listing country codes: the first two letters are the code for the country name, and the third corresponds where possible to the first letter of the currency name. The US dollar is USD because US is the country and D is the dollar. The numeric code follows the same logic, matching the numeric country code where it can.
That design decides what the code can record. It can record a country replacing its money, because a new currency name gives a new third letter. It has no way to record that one country's money has two issuers, because the issuer is not encoded.
The maintenance agency's machine-readable list, in the version published on 1 January 2026, carries exactly one Yemen row: the currency name Yemeni Rial, the alphabetic code, a numeric code and two minor units.
How one country came to have two issuing authorities
By a relocation that the other side did not follow.
The Aden-based institution's own site refers to Decree No. 119 of 2016, which it describes as moving the headquarters and operations management of the Central Bank of Yemen from Sana'a to the temporary capital of Aden. The same page records that the bank subsequently obtained local, regional and international recognition.
An authority in Sana'a continued to operate. Researchers on Yemen's economy now define the two formally: a government central bank under the internationally recognised government in Aden, and a separately controlled central bank in Sana'a running a parallel financial system. The condition has a name in that literature, the bifurcation of monetary policy, defined as competing authorities managing parallel systems with disparities in exchange rates, banking regulations and economic policies.
Recognition settles which institution the outside world deals with. It does not settle which notes circulate in a marketplace.
What made the notes themselves different
A printing order, and then a prohibition.
In January 2017 the Aden-based bank took its first delivery of newly printed rial banknotes from a Russian state printer, creating a physical distinction between notes issued before the relocation and notes issued after it.
The prohibition followed. A circular issued in Sana'a on 18 December 2019 ordered holders in the area it controls to hand over the notes it treated as illegal, in exchange for electronic currency or for banknotes printed before September 2016. The grace period ran to 17 January 2020, after which holders faced confiscation and possible imprisonment, with a ceiling on how much an individual could exchange.
From that point the two series were not two designs of one money. They were two monies with one code, and which one a person held depended on which part of the country they were in.
How the institutions that measure it cope
They stop treating it as one series.
The clearest evidence sits in the World Bank's own indicator table for Yemen, which splits its exchange rate line into two rows, one labelled Aden and one labelled Sana'a, for each year it reports, and titles its charts on the subject as the rial on different markets. Its Spring 2026 edition, reflecting the situation as at the end of March 2026, records under its own heading that monetary and financial fragmentation persisted, and calls the money circulating in the north the pre-2016 rial.
The same edition notes a second-order effect: the fragmentation of economic data between the two territories hampers both the analysis and the conduct of monetary policy. A divided currency divides the measurements taken of it.
The humanitarian analysis unit ACAPS reaches the same arrangement operationally, maintaining two separate exchange rate trackers and describing the result of the January 2020 ban as two currency areas.
| What the code records | What it cannot record |
|---|---|
| The country, through the first two letters | Which authority issued a particular note |
| The currency name, through the third letter | That two note series exist under one name |
| The number of minor units | That one series is prohibited where the other circulates |
| A replacement, if the currency is renamed | A division inside a currency that keeps its name |
What the split does to a payment
It removes the assumption that money is worth its face value everywhere.
A 2026 study of Yemeni remittances states the consequence directly: different notes in the north and south have fragmented the financial system, and a rial sent from Aden cannot be used at face value in Sana'a. Many transactions across the divide now take place in foreign currency instead, which adds conversion costs and depends on that currency being available.
Movements of this kind have their own category in that work, cross-line transfers: transfers crossing separate monetary, regulatory and enforcement regimes, frequently handled through informal channels.
The currency a recipient is paid in has also been directed rather than chosen. The same study records that in February 2024 a money exchange association in Sana'a required remittances to be paid out in the currency in which they were sent rather than converted into rials, and that in March 2024 the northern authority required transfers to be disbursed in Saudi riyals. When a unified transfer network was launched from Aden in July 2024, institutions under northern control were barred from registering with it.
When one side issues new money
The other side rejects it, and the rejection is public.
New issuance has continued from the Sana'a side: a fifty rial coin on 13 July 2025, and a two hundred rial banknote two days after that.
The Aden-based bank called the 2025 coin counterfeit, destructive, and a continuation of the economic war. The United Nations Special Envoy for Yemen said on 17 July 2025 that he was deeply concerned by the minting of the coin and the printing of the note, that such unilateral actions are not the solution to the liquidity crisis, and that they risk deepening the fragmentation of the country's monetary and institutional frameworks. The same statement records that the issuance violated an understanding reached on 23 July 2024 to de-escalate in the economic sphere.
That is the position the sources support as at the middle of 2026: the understanding was declared violated in July 2025, and no source consulted here describes it as functioning since.
What a code cannot carry
None of this is visible in the code, and none of it can be.
YER does exactly what the standard designed it to do. It names the country, the currency and the minor unit, unambiguously enough to be machine-readable. What it cannot record is that the money behind it is not fungible with itself, because no field was built to hold that.
So a payment instruction, a price list and a statistical series can each be correct in the code and still describe different things. That is why the bodies working on Yemen add a label the standard does not have, Aden or Sana'a, before the number means anything.
Where to look next
The AUD to YER page carries the live reference rate and a short block on money sent home to Yemen and why nobody knows how much. For a country running two different currencies side by side rather than one currency in two versions, how a country uses two currencies at once sets out that arrangement. Where several institutions lawfully issue notes of a single currency under one authority, who is allowed to print a pound covers what backs the private notes. Transfers of the kind this division makes hardest are set out under remittance.
Sources
- International Organization for Standardization, ISO 4217 currency codes - the alphabetic code built from the ISO 3166 country code, the third letter from the currency name, and the numeric code following the numeric country code
- SIX Group, ISO 4217 List One - the maintenance agency's list, published 1 January 2026, carrying one Yemen entry: Yemeni Rial, YER, with its numeric code and two minor units
- Central Bank of Yemen, Governor's Word - Decree No. 119 of 2016 moving the headquarters and operations management from Sana'a to Aden
- World Bank, Yemen Economic Monitor: Pushing Against the Tide, Spring 2026 - the separate Aden and Sana'a exchange rate rows, the charts titled as the rial on different markets, the finding that fragmentation persisted, the term used for the notes circulating in the north, and data fragmentation hampering monetary policy. Situation as at end-March 2026
- Office of the Special Envoy of the Secretary-General for Yemen, statement on the recent issuance of currency, 17 July 2025 - the concern at the coin and the note, the risk of deepening monetary and institutional fragmentation, and the violation of the 23 July 2024 understanding
- International Growth Centre, From cash to capital, February 2026 - the two central banks and the bifurcation of monetary policy defined, a rial sent from Aden not usable at face value in Sana'a, cross-line transfers, and the February and March 2024 requirements on the currency of disbursement
- Sana'a Center for Strategic Studies, The War for Monetary Control Enters a Dangerous New Phase, 21 January 2020 - the January 2017 delivery of newly printed notes, the circular of 18 December 2019, its grace period to 17 January 2020 and the enforcement that followed
- Sana'a Center for Strategic Studies, Currency War Threatens to Deepen Yemen's Monetary Rift, 18 July 2025 - the coin of 13 July 2025, the note announced two days later, and the Aden bank calling the coin counterfeit, destructive, and a continuation of the economic war
- ACAPS, Yemen Economic Tracking Initiative - two separate exchange rate trackers, and the account of the January 2020 ban producing two currency areas
General information about how currency codes and note issuance work. Not financial advice, and not a recommendation of any product or institution. Nothing here states or implies the value of any currency. Reviewed by the Tradergy editorial team, September 2026.
Common questions
Can one country have two central banks?
In practice yes, where control of the territory is divided. Yemen has had two bodies acting as the Central Bank of Yemen since 2016, when a presidential decree moved the headquarters and operations management to Aden while an authority in Sana'a continued to operate. International recognition attaches to one of them, but recognition does not stop the other issuing money inside the area it controls.
Why does ISO 4217 not give them separate codes?
Because the code identifies a country rather than an issuer. ISO explains that the first two letters of the three-letter code are the same as the country code in ISO 3166, with the third letter usually the first letter of the currency name. A dispute about who issues the money inside one country does not change the country, so nothing in the structure of the code has anything to divide.
What is the difference between an old rial and a new rial?
The distinction is the date of issue. Analysts covering Yemen define old rials as banknotes issued before 2017 and new rials as those issued after that by the Aden-based authority, which took delivery of newly printed notes in January 2017. The World Bank refers to the money circulating in the north as the pre-2016 rial. The two descriptions rest on the same event and differ by a year in how they are phrased.
Are the two note series interchangeable?
No. A circular issued in Sana'a in December 2019 prohibited notes printed after September 2016 in the area it controls, with a grace period that ran to 17 January 2020, and enforcement that included confiscation. Researchers writing in 2026 put the consequence plainly: a rial sent from Aden cannot be used at face value in Sana'a.
Does this show up in official statistics?
Yes, and that is the clearest evidence it is real. The World Bank's Yemen Economic Monitor carries an exchange rate line split into two rows, one labelled Aden and one labelled Sana'a, for each year in its indicator table, and titles its charts as the rial on different markets. The humanitarian analysis unit ACAPS maintains two separate exchange rate trackers for the same reason.