Switching from JIBAR to ZARONIA: Key Information

15 September 2025

As part of South Africa’s shift to safer, more transparent benchmark rates, the Johannesburg Interbank Average Rate (JIBAR) will be replaced by the South African Rand Overnight Index Average (ZARONIA). This article outlines the upcoming changes, explains the rationale, presents the implementation timeline and describes how Ashburton Investments is supporting a smooth transition.

What Is ZARONIA?

ZARONIA serves as the new benchmark rate for rand-denominated overnight wholesale funding transactions. Endorsed by the South African Reserve Bank (SARB), it is calculated from actual overnight lending transactions, providing a more reliable and transparent measure of funding costs. It will serve as a reference for a wide range of financial products, including savings & investments, loans, bonds, and derivatives. By replacing estimated interbank quotes with real-time data, ZARONIA reduces the risk of rate-setting errors and manipulation.

Why the Transition Matters

Unlike JIBAR, which is based on indicative quotes from a small group of banks and is vulnerable to misrepresentation, ZARONIA is calculated from actual overnight transactions reported daily across a broad range of institutions, delivering a transparent and accurate reflection of true market activity.

If you have savings, fixed‑rate investments, or money‑market products linked to JIBAR, the reference rate used will be changing. Any small financial differences will be balanced out using an industry rolled out spread mechanism to keep things fair and neutral. New products will start to reference ZARONIA from the outset. Behind the scenes, we’ll work with issuers and industry partners to make the necessary updates smoothly.

Ashburton Investments Readiness

Ashburton Investments has collaborated with platform providers, custodians and back-office partners to ensure full system compatibility with ZARONIA. We executed our first ZARONIA-linked trade on day one of market go-live, demonstrating operational preparedness and commitment to uninterrupted service.

How This Affects Your Existing and New Investments

• Existing JIBAR-linked investments will move to ZARONIA automatically after JIBAR’s end-of-2026 cessation date.
• A credit adjustment spread (CAS) will be applied so your repayments or yields stay roughly the same, neither higher nor lower just because of the switch.
• New products can already reference ZARONIA, and from March 2026 all new contracts must use ZARONIA instead of JIBAR.

Next Steps and Support

Ashburton Investments will manage the technical and administrative aspects of the JIBAR-to-ZARONIA transition on behalf of our clients. Any required contract updates or detailed information will be communicated directly.

For additional details or enquiries, please contact:

T +27 (0)86 000 0339 | F +27 (0)11 384 3939 Email: SARatesReform@ashburton.co.za www.ashburtoninvestments.com

Ashburton Fund Managers Proprietary Limited (Reg 2002/013187/07) is an authorised financial services provider (FSP 40169). Part of the FirstRand Group.