Bank of Korea Rate Hikes Push Mortgage Rates to 45-Month High

Two hikes in, and borrowers are already paying more

The Bank of Korea raised its benchmark rate by a quarter point to 3.00% on August 27. It was the second increase in a row, following July's move from 2.50% to 2.75%.12 Coverage widely describes this as the first back-to-back tightening since early 2023. Governor Shin Hyun-song went further and called the consecutive hikes "unprecedented" in the strong signal they sent to markets.414 The decision was not unanimous. Six of the seven Monetary Policy Board members backed it, and Hwang Gunil voted to hold at 2.75%.919

The headline decision is old news by now. What has happened since is more important: commercial bank lending rates have risen faster than the policy rate itself. A household borrowing in Seoul now faces conditions that look tighter than a 3% base rate would suggest. With the next policy meeting set for October 22, that gap is becoming the main issue for both the central bank and the country's lenders.14

Why the BOK moved: a chip boom running into an oil shock

Reporting on the BOK's reasons is unusually consistent. Inflation has run above the 2% target for months, driven by the energy shock from the Iran conflict. At the same time, the economy has grown much faster than expected on a semiconductor upcycle fed by global AI demand.39 Headline consumer inflation reached 3.2% in June before easing to 2.8% in July. Core inflation rose to 2.6% in July, its highest since December 2023.35 By September core inflation had reached 2.8%.17

The growth numbers are what made back-to-back hikes defensible. The BOK raised its 2026 growth forecast to 3.3% from 2.6%.1 Second-quarter gross domestic income rose by roughly 15.6% to 15.7% year on year, depending on the outlet.414 Capital Economics noted after the July hike that exports in June grew at their fastest pace since 1978, and argued the economy could absorb higher rates.5

Housing is the third factor. CNBC reported that Seoul home prices rose 2.5% month on month in June, the fastest in five years.3 In its October 12 report to the National Assembly, the BOK named rising home prices in the Seoul metropolitan area and growing household debt as major financial-stability risks. It said household lending has expanded mainly through housing-related loans.28

The pass-through: lending rates are rising faster than the base rate

The BOK's August data on financial institution rates shows how quickly tighter policy reached bank customers. The weighted average rate on new bank loans rose 13 basis points to 4.40%. Rates on new household loans climbed to 4.76%, the highest since November 2024.21

Mortgages saw the sharpest change. The average bank mortgage rate rose 18 basis points in one month to 4.66%. That was its fourth straight monthly increase and its highest level since November 2022.21 Fixed-rate mortgages reached 4.88%, their eleventh consecutive monthly increase. Variable-rate mortgages rose to 4.53%.22 Unsecured personal loans rose 36 basis points to 6.33%, breaking above 6% for the first time since December 2024.2122

A BOK official acknowledged that market rates had risen considerably more than the base rate. Lending and deposit rates have both been trending up since the second half of last year.21 Data through late September showed market rates up another 20 basis points, which led BOK statisticians to expect further increases in lending rates.

The effect on individual borrowers is significant. At the five largest banks, variable mortgage rates were quoted between 4.35% and 6.72% in late September, up from 4.02% to 6.37% in mid-July. On a 300 million won loan, that 33-basis-point rise in the lowest rate adds about 80,000 won a month in interest.27 New mortgages priced at 5% or more at the five major banks rose about fourteenfold between December and August, to roughly 2.34 trillion won. Across all 16 domestic banks, loans above 5% now make up 32.5% of new mortgages, up from 14.7%.25

Banks' margins and funding costs: two explanations for the same result

On the banking side, the reporting gives two explanations that do not fully match. One focuses on bank margins. Savings deposit rates were flat at 3.21% in August while lending rates rose. That widened the gap between lending and deposit rates to 1.19 percentage points from 1.06.22 Seoul Economic Daily also reported that the average spread on new installment mortgages at the big five banks was still at a record 3.26% in July, which suggests lenders are charging more on top of base rates.27

The other explanation focuses on funding costs. Woori Bank raised its one-year corporate time deposit rate to 4.09% at the end of September, up 0.44 points from late August. NH NongHyup and Shinhan pushed their rates into the high-3% range. Corporate clients supply about 80% of bank time deposits.24 Yields on five-year AAA bank debentures, the benchmark for fixed and hybrid mortgages, reached about 4.6%, up from 3.49% at the end of last year. The 30-year U.S. Treasury yield also rose above 5.6%.24 Bankers argue that higher deposit costs lead to higher loan rates with a delay. Some in the industry expect the top end of mortgage pricing to pass 8% before the end of the year.24

Both accounts are probably true, but they apply to different periods. August's flat deposit rate and wider spread were good for bank margins in the short term. September's competition for deposits suggests that advantage is shrinking as funding costs catch up. The BOK itself noted that deposit rates jumped 13 basis points in July and described the overall trend as clearly rising.21 The likely result is that lending rates will keep rising even if the BOK pauses in October.

Early signs of slower credit growth

Tighter policy is starting to slow lending. Household loan balances at KB Kookmin, Shinhan, Hana, Woori and NH NongHyup fell by about 1.29 trillion won in September, their first drop in six months.26 Credit loans, which had risen by more than 5.4 trillion won from May to July as retail investors borrowed to buy stocks, fell by about 1.3 trillion won. Growth in mortgage balances nearly stopped, at just 125 billion won.26

Borrowers are also changing their behavior. The fixed-rate share of new mortgages rose to 35.3% in August from 31.9%, the first increase in ten months.22 That matters because 68.1% of new mortgages in July had variable rates, so most borrowers feel rate increases almost immediately.27 The BOK estimates that each quarter-point increase in the policy rate adds 3.3 trillion won to household interest payments and 3.7 trillion won for companies.16

Divided forecasts for October

Forecasters agree on the direction of rates but not the timing. After the August decision, Reuters described the median expectation as one more hike in the first quarter of 2027 and then a long hold. One analyst said the board appeared certain to hold in October.1 The BOK's dot plot put 3.25% as the most likely rate at the end of 2026, with six of the 21 dots at 3.50%.1 United Overseas Bank expects one final hike to 3.25% in the fourth quarter.9 Trading Economics' model predicts that hike on October 22.4 Citi expects increases in November and February, which would take the rate to 3.5%.1625

Recent comments from Shin lean hawkish. At the October 12 parliamentary audit, he said inflation would stay above target for "a considerable period" as built-up cost pressures and demand-side pressure feed through. He stressed controlling core inflation early.1517 He presented the July and August hikes as buying time, saying the BOK moved before the Federal Reserve's September increase and that acting early costs less than raising rates defensively later under market pressure.1320 He declined to say when the next increase would come or how fast further hikes would be, and promised to explain at the October meeting.13

Analysis: the tightening may already be happening without the BOK

In practice, the BOK's forward guidance has already done part of its job. Shin argues markets priced in the tightening cycle in May and June.13 Bank lending rates are now rising on their own momentum, pushed by deposit competition, higher debenture yields and rising long-term rates abroad.2428 Seen this way, an October pause is not a dovish move. It gives the BOK time to see how much of the next hike the banks have already passed on to borrowers.

The weakest point in the case for tightening is the policy mix. Lawmakers have argued that government fiscal expansion is working against monetary tightening, and that vulnerable borrowers end up carrying the cost.1617 Shin estimates next year's budget adds only 0.06 percentage points to inflation.20 The BOK's own report, however, warns that defaults could rise among self-employed borrowers and smaller firms whose incomes are not keeping pace.28 HSBC's Frederic Neumann made a similar point: the expansion is unbalanced, and gains from AI hardware have not spread into broad consumer spending.3 For Korea's banks, that means more loans repricing above 5%, deposit costs that are still rising, and borrowers who may become strained before the BOK finishes tightening.