We Analysed 23 Years of SA Rates: Prime Fell and Borrowing Got Dearer
Between 2023 and 2025 the prime lending rate came down. Most people read that as borrowing getting cheaper.
We ran the numbers, and it did not. After inflation, debt in 2025 cost more than in any year since 2004.
What we did
Two datasets, both already published on this site with their sources attached.
Prime rate history — every change to the prime lending rate, 64 of them, from December 2001 to May 2026.
CPI — Statistics South Africa's headline consumer price index (publication P0141, Table B1), annual averages, all on a single Dec 2024 = 100 base.
For each year we computed the day-weighted average prime rate — prime is a step function, so we walk every day of the year, take the rate actually in force, and average it. A rate cut in November counts for the six weeks it applied, not for a whole year.
Then annual inflation from the index ratio rather than from chaining published rates, which compounds rounding error across two decades. Subtract one from the other and you get the real prime rate: what borrowing costs after inflation erodes the debt.
Before drawing any conclusion we checked the pipeline. The CPI dataset's own notes list six inflation figures its author verified against published history. Our independent computation reproduces all six to within 0.05 of a percentage point.
The 23 years
| Year | Average prime | Inflation | Real prime |
|---|---|---|---|
| 2003 | 15.11% | 5.97% | +9.13 |
| 2004 | 11.31% | 1.19% | +10.12 |
| 2005 | 10.64% | 3.52% | +7.12 |
| 2006 | 11.13% | 4.82% | +6.32 |
| 2007 | 13.12% | 6.76% | +6.36 |
| 2008 | 15.11% | 11.65% | +3.47 |
| 2009 | 11.88% | 6.58% | +5.30 |
| 2010 | 9.90% | 4.26% | +5.65 |
| 2011 | 9.00% | 5.10% | +3.90 |
| 2012 | 8.77% | 5.44% | +3.34 |
| 2013 | 8.50% | 5.89% | +2.61 |
| 2014 | 9.07% | 6.09% | +2.99 |
| 2015 | 9.39% | 4.59% | +4.80 |
| 2016 | 10.41% | 6.43% | +3.98 |
| 2017 | 10.39% | 5.15% | +5.23 |
| 2018 | 10.09% | 4.76% | +5.32 |
| 2019 | 10.14% | 4.01% | +6.13 |
| 2020 | 7.85% | 3.34% | +4.51 |
| 2021 | 7.03% | 4.48% | +2.55 |
| 2022 | 8.60% | 6.90% | +1.70 |
| 2023 | 11.41% | 5.90% | +5.51 |
| 2024 | 11.65% | 4.42% | +7.24 |
| 2025 | 10.74% | 3.22% | +7.52 |
The mean across the whole period is +5.25 percentage points.
Finding 1: the rate fell and the cost rose
Look at the last three rows together.
| 2023 | 2024 | 2025 | |
|---|---|---|---|
| Average prime | 11.41% | 11.65% | 10.74% |
| Real prime | +5.51 | +7.24 | +7.52 |
Nominal prime peaked in 2024 and then fell. The real cost of borrowing rose anyway, and kept rising — because inflation fell faster than the rate cuts did. Prime came down by about 0.9 of a point on the annual average; inflation came down by 1.2.
At +7.52pp, 2025 was the most expensive year to owe money since 2004, and sat 2.27 percentage points above the 23-year average.
That is the gap between how borrowing felt and what it cost. Three cuts in a row is an unambiguously good headline. It was not an unambiguously good year to be in debt.
Finding 2: you have never been paid to borrow here
In the 23 years we measured, the real prime rate was never negative — not once, not in any single year.
That is worth stating precisely, so here is the scope: our prime series begins in December 2001, so this is a statement about 2003 to 2025, not about all of South African history.
Within that window it is unbroken. Even in 2008, with inflation at 11.65%, prime averaged 15.11% and the real rate stayed at +3.47. Even at the record-low 7.00% prime of the pandemic, inflation was low enough that real rates stayed firmly positive.
Borrowers in several developed economies spent parts of the last decade with inflation running above their borrowing rate. That has not happened here in the period we can measure.
Finding 3: the cheapest money was not when you think
Ask when South African debt was cheapest and most people say 2020 — prime at 7.00%, the lowest on record.
The data says otherwise. The two cheapest years in real terms were 2022 (+1.70pp) and 2021 (+2.55pp) — and 2022 is the year prime was rising, through four consecutive 75-basis-point hikes.
2020 ranks mid-table at +4.51, worse than five other years, because inflation had collapsed to 3.34%. A 7.00% rate against 3.3% inflation is a worse real deal than an 8.6% rate against 6.9% inflation.
The lesson is not that the headline rate is irrelevant — it sets your cash instalment, and cash flow is real. But the rate alone never told you what the debt was costing you.
What this is worth in rands
Real rates do not change your monthly instalment. They change what the debt costs you in purchasing power once inflation has done its work on the balance.
On R1,000,000 of debt, a real rate of +7.52pp rather than the historical +5.25pp average is a difference of about R22,700 a year in real terms. Across a bond that runs for two decades, an era of persistently above-average real rates is a materially different proposition from the one your parents borrowed into.
That is an illustration of scale, not a quote for your account. Your actual instalment depends on the nominal rate, your margin above or below prime, and the term.
Where we stand now
Prime today is 10.50%, after the May 2026 increase.
We are deliberately not printing a 2026 inflation rate. The most recent CPI month in our data is June 2026 at an index of 107.5. Measured against the 2025 annual average that implies roughly 4.9% — but that compares a single month to a twelve-month average, and it is an approximation, not an official year-on-year figure.
Read loosely, it puts the current real rate somewhere near the long-run mean rather than at the 2025 extreme — inflation appears to have picked up while prime moved up only 25 basis points. We would rather give you that shape than a decimal we cannot stand behind.
Method, and what would break it
Annual averages, not point-in-time. A year in which prime changed in December looks close to the year before it. That is deliberate — it reflects what borrowers actually paid over the year.
The 2009 break. Stats SA changed how CPI is compiled in January 2009, moving from primary urban areas to all urban areas. It linked the series so it stays continuous, which is what makes the long comparison usable — but any comparison spanning 2009 crosses two slightly different baskets. We are telling you rather than hiding it.
Prime is not your rate. Most borrowers pay prime plus or minus a margin. The series measures the benchmark, not your agreement.
This measures, it does not explain. Nothing here is a claim about why the Reserve Bank did what it did, and there is no forecast on this page.
About the data
Prime rate history from this site's own prime rate history dataset — 64 changes from December 2001 to May 2026, validated by its compiler against five independent anchor points. Inflation from Statistics South Africa, CPI headline index numbers, publication P0141, Table B1, base Dec 2024 = 100, parsed programmatically from the Stats SA release rather than transcribed.
All calculations above are ours. Figures are annual averages and will not match a point-in-time quote. This is analysis, not financial advice.
How does this affect YOUR Money OS?
If you have been waiting for rates to fall before dealing with debt, the last three years are a caution: the headline fell and the real burden did not. The number that decides whether debt is getting easier is the gap between your rate and inflation, not the rate on its own.
FAQ
What is the real prime rate? The prime lending rate minus inflation — what borrowing costs after inflation erodes the value of the debt.
What was it in 2025? +7.52 percentage points, on a day-weighted average prime of 10.74% and inflation of 3.22%. That is the highest since 2004.
Did borrowing get cheaper as rates fell? Not in real terms. Real prime rose from +5.51 in 2023 to +7.24 in 2024 to +7.52 in 2025, because inflation fell faster than the rate cuts.
Has the real prime rate ever been negative in South Africa? Not in the 23 years we measured (2003 to 2025). Our prime series starts in December 2001, so we make no claim about earlier periods.
When was borrowing cheapest in real terms? 2022, at +1.70 points, followed by 2021 at +2.55 — not 2020, despite 2020 having the lowest nominal rate on record.
What is the long-run average? +5.25 percentage points across 2003 to 2025.
What is inflation now? We are not publishing a 2026 figure. The latest CPI month in our data is June 2026; compared with the 2025 annual average it implies roughly 4.9%, which is an approximation rather than an official year-on-year rate.
Where does the data come from? Stats SA's CPI headline index (P0141, Table B1) and this site's prime rate history dataset. The calculations are ours.
