South Africa’s banking sector is undergoing a major shift. In a bid to modernise the country’s financial system, the South African Reserve Bank (SARB) is driving a change to the primary interest rate benchmark. This will impact anything from simple loans to complex financial investments.
What’s changing and why?
South Africa’s current benchmark interest rate, JIBAR (the Johannesburg Interbank Average Rate), is a term rate with multiple tenors, (1-month, 3-month, 6-month, and 12-month). It is determined by averaging interest rate submissions from major banks; however, these rates reflect indicative borrowing costs rather than actual transactions.
JIBAR is to be replaced by ZARONIA (the South African Rand Overnight Index Average), a risk-free overnight rate based on actual market transactions. With a volume-weighted methodology, ZARONIA provides a more accurate and reliable measure of market activity and is therefore a better reflection of real-time financial conditions.
A global shift towards transparency
South Africa’s transition to ZARONIA aligns with a broader global move toward more reliable financial benchmarks. This shift was largely prompted by past controversies exposing weaknesses in traditional reference rates including the 2012 LIBOR (London Interbank Offered Rate) scandal where major banks manipulated rate submissions for financial gain. In response, global markets adopted transaction-based alternatives such as the Secured Overnight Financing Rate (SOFR) in the US, and Sterling Overnight Index Average (SONIA) in the UK. The LIBOR transition was a complex seven-year process, setting an international precedent from which South Africa can benefit.
Key adjustments
The transition to a new interest rate benchmark may require adjustments on contractual obligations linked to the “outgoing” rate, JIBAR. Historically, the 3-month JIBAR rate, the most widely used benchmark in South African financial markets, has carried a premium over ZARONIA due to embedded credit and term risk. As shown in Chart 1, the exact premium or differential between the two fluctuates based on market conditions and plays a crucial role in determining the “fallback” rate. This rate will be used for JIBAR-linked contracts that do not voluntarily transition before JIBAR is phased out. For example, if a current contract specifies JIBAR+150 basis points, it may be adjusted to ZARONIA+180 basis points, if the fallback rate is set at 30 basis points.
Chart 1: Difference JIBAR vs ZARONIA
When is the transition happening?
The staged transition is already underway with a full switch expected by the end of 2026. The South African Reserve Bank (SARB) will finalise the fallback rate methodology for cash products and derivatives by June 2025 and December 2025, respectively. To avoid last minute disruptions, financial institutions and stakeholders are encouraged to proactively update current contracts before the proposed deadline. This approach will ensure a smooth transition while maintaining market stability.
What does this mean for stakeholders?
For Individual Borrowers: Owners of financial products tied to JIBAR, will be informed by their bank of any contractual changes. The shift should have minimal impact on interest payments, as banks will apply adjustments to maintain customer fairness.
For Businesses: Companies should review loan agreements, derivatives, and financial models to ensure a seamless transition. This includes updating treasury systems, refining risk models, and coordinating with financial partners to align with the new framework.
For Investors: Investment managers will be adjusting fund performance benchmarks, valuation methods, and financial products to reflect ZARONIA. While core investment strategies remain intact, staying informed of changes is key.
Potential challenges:
The transition presents some challenges which the financial sector is actively addressing. These include:
- System Updates: Banks and financial institutions must upgrade their technological infrastructure to accommodate ZARONIA calculations. Regular industry-wide testing is ensuring systems are prepared.
- Contract Remediation: Updating existing contracts is a complex process. Standardised templates, and legal oversight are streamlining the transition while maintaining fairness in contract conversions.
- Market Liquidity: To build robust trading in ZARONIA-linked products, market makers are having to develop new instruments and hedging tools to enhance market depth.
A move towards transparency
While the transition demands significant effort, it is a crucial step toward a more transparent and resilient financial system. Beyond aligning South Africa with international benchmark reforms, the shift to ZARONIA is expected to enhance market efficiency and strengthen investor confidence.
The success of this transition will depend on proactive engagement from all stakeholders and clear communication throughout the process. The SARB has established a Market Practitioners Group (MPG) to provide guidance, including contract templates and conversion methodologies and they remain actively available to support financial institutions, ensuring a smooth and well-coordinated shift by the end of 2026.
Truffle continues to support and monitor the progress of the ZARONIA transition and will adjust performance benchmarks on our fixed income funds when appropriate from a market timing perspective.
