If you have a bond, a car finance agreement, a personal loan, or an overdraft in South Africa, there is a reasonable chance the rate on it is expressed as something like “prime plus 2” or “prime less 0.5”. That reference is being retired.
In February the Reserve Bank published a consultation paper proposing the cessation of the prime lending rate and its replacement, for retail lending, with the SARB policy rate — the repo rate. It is not a small piece of housekeeping. The paper puts the scale at more than 12 million contracts referencing prime, worth over R3.2 trillion, with retail mortgages and consumer loans making up roughly 37% of that exposure.
Almost nobody has written about this for the people who actually hold those 12 million contracts, so here it is: what prime is, why it is going, what the arithmetic looks like, and the one thing worth checking when your agreement gets re-papered.
The thing about prime that most people never learn
Prime feels like a market rate. It is announced, it appears in the news, banks all quote the same number, and it moves in a way that looks disciplined and official.
It is not a market rate. Prime is a convention. It is a rate the banks set, and in South Africa it has sat at the repo rate plus 3.5 percentage points for years by common practice rather than by rule. Right now the repo rate is 7% and prime is 10.5%, which is exactly that 3.5% spread. When the Monetary Policy Committee moves the repo rate, the banks move prime by the same amount, and the spread holds.
So prime is a number derived from another number, maintained by convention among the institutions that benefit from it, and not anchored to any actual transactions. That is the problem. After the LIBOR scandal, regulators worldwide spent a decade moving away from benchmarks that are set by judgement or convention rather than observed activity. South Africa is doing its version of that work.
You may also have seen ZARONIA mentioned in this context, and it is worth clearing up because the two reforms get conflated. ZARONIA — the South African Rand Overnight Index Average — is built on actual overnight interbank transactions, which makes it very hard to manipulate, and it is replacing JIBAR. That transition is in its final stages and is targeted to complete by the end of 2026. But the consultation paper is explicit that ZARONIA is not the intended replacement for prime in retail lending. The SARB considered it and concluded it would add unnecessary complexity for consumer contracts. ZARONIA is for wholesale markets. For your bond, the proposal is the repo rate.
The arithmetic, which is deliberately boring
This is the part to internalise before you read anything alarming about it elsewhere: the reform is designed to be economically neutral. Your rate does not change. The way it is written down changes.
Because prime is repo plus 3.5, any margin against prime converts cleanly to a margin against repo by adding 3.5:
Prime less 1 becomes repo plus 2.5. Prime flat becomes repo plus 3.5. Prime plus 2 becomes repo plus 5.5.
Run it on a real bond. You are at prime less 0.5, so 10% today with prime at 10.5%. After conversion you are at repo plus 3, which with repo at 7% is 10%. Same rate. Same instalment. Same total interest over the remaining term. The SARB has been clear that the change is intended to have no economic impact and that interest payments should remain unchanged.
What genuinely improves is transparency. Under the current arrangement your rate depends on a bank-maintained convention sitting on top of a policy decision. Afterwards it references the policy rate directly — a number set publicly by the MPC at scheduled meetings, with published minutes and a recorded vote. There is one less layer between the decision and your instalment, and that layer was the one nobody could audit.
When this actually happens
Not soon, and this matters because there is no action required from you today.
The active transition is sequenced behind the JIBAR cessation process, which needs to complete first. On the current view, 2027 is the earliest realistic start, and the migration will be phased so banks can rebuild systems, redraft documentation, and communicate to retail customers without generating mass confusion. Twelve million contracts do not get re-expressed in a weekend.
What you will see, when it comes, is correspondence from your bank explaining that your rate is being restated. Not renegotiated. Restated.
The one thing worth checking
Here is where I want to be precise, because there is a difference between raising a legitimate point and manufacturing alarm about a technical reform.
The reform itself is neutral and there is no reason to expect banks to use it as cover for repricing. Contractual margins are contractual, the NCA governs unilateral variation of credit agreements, and a coordinated attempt to widen spreads through a regulator-led transition would be visible and consequential.
But 12 million contracts are going to be re-expressed by institutions running migrations across old systems, and the arithmetic that carries your specific margin across is a per-contract operation. In any exercise of that size, some proportion of records will be handled incorrectly. Not maliciously — just wrongly, the way large data migrations always produce a tail of errors.
Which is why the useful thing to do costs about five minutes and is worth doing now, well ahead of any notice arriving.
Find your credit agreement and write down exactly how your rate is expressed. Not the percentage — the formula. “Prime less 0.5” or “prime plus 1.75”, whatever it says. Note the agreement number and the date. Keep that somewhere you will find it in two years.
Then, when the restatement notice arrives, do the addition. Your old margin against prime, plus 3.5, should equal your new margin against repo. If your bond said prime less 0.5 and the notice says repo plus 3, that is correct. If it says repo plus 3.25, that is a quarter of a percentage point that should not be there, and on a R1.2 million bond over 20 years a quarter point is roughly R190 a month — something in the region of R45,000 over the remaining term.
Nobody is going to check that for you. The margin is in a document you signed years ago, possibly at a different bank, possibly on a bond you have since switched. The bank’s notice will look authoritative and most people will file it without doing the sum.
What this does not change
A few things worth saying plainly, because rate reform stories tend to attract confusion.
Your instalment does not change because of this. If your repayment moves, it moved because the MPC changed the repo rate, which is what has always driven it.
Fixed-rate agreements are unaffected. If your rate is fixed, there is no prime reference to convert.
Short-term and unsecured lending mostly does not reference prime at all. Payday-type credit and small personal loans are priced against the NCA caps — 5% a month on a first short-term loan, 27.75% APR on unsecured personal loans — not against prime. If you are borrowing R3,000 for 30 days, this reform has nothing to do with you.
And it is not a rate cut or a rate hike. The repo rate was held at 7% on 23 July, with inflation up to 5% in June and the committee splitting four-to-two. That is the thing that determines what you pay. Whether it is described as prime less 0.5 or repo plus 3 is bookkeeping.
Why bother knowing about it
Because in about a year and a half, twelve million South Africans are going to receive a letter about their loan that they do not understand, and the ones who wrote down their margin beforehand will be able to verify it in thirty seconds while everyone else takes the bank’s arithmetic on faith.
That is the whole value of reading about a technical reform early. Not because anything dramatic is going to happen, but because the small window in which a mistake is easy to catch opens and closes quickly, and it favours the people who already knew the change was coming.
— Romans
The SARB consultation paper is public and readable if you want the source material. This is general information, not financial or legal advice on your specific agreement.