The South African Rand Overnight Index Average (ZARONIA) reflects the interest rate at which rand-denominated overnight wholesale funds are obtained by commercial banks. It is based on actual transactions and calculated as a trimmed, volume-weighted mean of interest rates paid on eligible unsecured overnight deposits.
On 2 November 2022, the SARB commenced publishing ZARONIA primarily to allow market participants to observe its performance and consider the implications of adopting it as a replacement for the Johannesburg Interbank Average Rate (Jibar). The observation period ended on 3 November 2023. Certain observation period statistics have been restated to reflect revisions that were processed post their publication. Market participants may use ZARONIA as a reference rate in financial contracts.
The Market Practitioners Group has designated ZARONIA as the successor rate to replace Jibar.
ZARONIA is published every South African business day at 10:00. The benchmark rate may be republished at any time before 12:00 in the event that an error is discovered after the standard publication of the benchmark at 10:00. The calculation methodology and policies governing ZARONIA are prescribed in the Technical Specification Paper.