ISIN change

When a security receives a new ISIN — for example due to a corporate merger, restructuring, or regulatory change — all holdings must be transferred from the old to the new security. GT supports this process as a system-wide action: an administrator creates the ISIN change once, and each affected tenant can apply it to their own holdings.

Workflow overview

The following diagram shows the typical workflow of an ISIN change — from discovery by the user to application on their own holdings:

sequenceDiagram
    participant U as User
    participant S as System (GT)
    participant A as Administrator

    U->>S: Discovers ISIN change<br/>(e.g. via watchlist)
    U->>A: Reports ISIN change<br/>via internal mail
    A->>S: Creates ISIN change<br/>(System Actions)
    S->>S: References existing or creates<br/>new security, counts affected tenants
    S->>S: Copies connector settings and<br/>loads historical price data
    S->>U: Notification<br/>via internal mail
    U->>S: Applies ISIN change
    S->>S: Reassigns transactions from action<br/>date onwards to new security
    S->>S: Generates sell (old ISIN)<br/>and buy (new ISIN)
    S-->>U: Status: Applied

Administrator workflow

The administrator creates an ISIN change in the Security action TreeTable by right-clicking on the root node System Actions (ISIN Changes) → Create ISIN change.

Dialog fields

After saving, GT references the existing security or creates a new one with the specified ISIN, counts the affected tenants, and sends them an internal mail notification about the available ISIN change. When GT creates a new security, it automatically copies the data feed configuration from the old security and starts loading historical price data in the background.

Deleting an ISIN change

The administrator can remove an ISIN change via right-click → Delete ISIN change. This is only possible as long as no tenant has applied the action.

User workflow

Applying an ISIN change

Once an administrator has created an ISIN change, every affected tenant sees the action in their TreeTable with the status Not applied. To apply the change: right-click on the corresponding row → Apply ISIN change.

GT then performs the following steps:

1. All existing transactions of the tenant on or after the action date that reference the old security are reassigned to the new security. This includes dividends, buy/sell transactions, and any other operations recorded after the ISIN change took effect.
2. The closing price of the old security on the action date is retrieved.
3. For each affected securities account, a sell transaction for the old security and a buy transaction for the new security are generated based on the remaining pre-action-date holdings.
4. If split factors are set (From units / To units not equal to 1:1), the unit count and price on the buy side are adjusted accordingly.
5. The status changes to Applied.

Reversing an ISIN change

An already applied ISIN change can be reversed via right-click → Reverse ISIN change. This deletes all automatically generated sell and buy transactions. The status changes to Reversed. The action can then be applied again.

Practical examples

Inverse and leveraged ETFs lose value over time due to the daily reset mechanism and so-called volatility decay. When the price falls too far, issuers perform a reverse split to maintain minimum exchange listing prices. In the USA, a reverse split requires a new CUSIP number and thus also a new ISIN, as the security structure changes substantially. Such ISIN changes with a simultaneous split are a typical use case for the GT function.

Examples: ProShares inverse ETFs

Recording in GT

For the ProShares Short QQQ example, the administrator would record the ISIN change as follows: select the instrument with ISIN US74347B7148 as the Old security, enter US74349Y8378 as the New ISIN, and set the Action date to 2024-04-10. Since a reverse split of 1:5 occurred simultaneously, From units is set to 1 and To units to 5. When applied, GT then generates the corresponding sell and buy transactions with adjusted unit counts.