An analysis says that if South Jeolla and Gwangju complete an administrative merger and launch as the "South Jeolla–Gwangju Integrated Metropolitan City," they could immediately rise to become the nation's No. 2 city by economic size. Significant changes are also expected in the long-standing rivalry between Incheon and Busan for the spot behind Seoul.
In particular, Incheon, which has recently overtaken Busan in gross regional domestic product (GRDP) and solidified its position as the "second capital," now faces a new variable.
According to the Ministry of Data and Statistics (MODS) on the 9th, as of 2024 the combined GRDP of South Jeolla and Gwangju totaled 158.8076 trillion won (nominal, preliminary). South Jeolla accounted for 103.9709 trillion won and Gwangju 54.8367 trillion won. Viewed separately, the two regions' economies are mid-tier nationally. Among the 17 cities and provinces, South Jeolla ranked eighth and Gwangju 15th.
GRDP is an indicator that sums the value of goods and services produced in a region over a given period, a concept similar to national-level gross domestic product (GDP). It is the most widely used metric when comparing regional economic size.
Gwangju alone fares even worse. It is effectively at the bottom among the eight special and metropolitan cities. The lowest, Sejong, is an administrative city launched in 2012 to promote balanced national development, centered on government complexes. Its industrial base and urban infrastructure are inevitably relatively weak.
Even so, Sejong outpaces Gwangju on some indicators. Sejong's per capita GRDP is 44.61 million won, higher than Gwangju's 37.68 million won. Regional gross income and regional net income are also larger in Sejong.
However, if Gwangju merges with South Jeolla, the picture changes. On a simple combined basis, in 2024 the two regions' GRDP would be the second largest after Seoul among the eight special and metropolitan cities. It would be more than 33 trillion won larger than Incheon (125.5919 trillion won), which had been No. 2.
In that case, Incheon would face a higher chance of yielding its second-capital status. Incheon has rapidly grown its economic size in recent years. In 2023 it overtook Busan in GRDP for the first time, and widened the gap in 2024. At the time, Incheon's GRDP was 125.5919 trillion won, more than 4 trillion won higher than Busan's 121.0669 trillion won.
Incheon has worked hard to attract corporations to catch up with Busan. Centered on SK Incheon Petrochem, the Seoul metropolitan area's only petrochemical complex, it built a refining and petrochemical industrial base and, leveraging its geographical advantages, grew into a Northeast Asia export hub.
The bio industry has also expanded quickly around Songdo. Corporations in contract manufacturing (CMO) of biopharmaceuticals and in biosimilars have moved in one after another. Samsung Biologics, Celltrion, and SK bioscience are representative.
Population trends are similar. According to the Ministry of Data and Statistics (MODS) population projections, Incheon's population in 2030 will be 3.10 million and Busan's 3.11 million, nearly the same. At the same time, Gwangju is projected at 1.40 million and South Jeolla at 1.71 million. Combined, the two would total 3.11 million, similar to Busan.
Some observers say that if a South Jeolla–Gwangju merger becomes reality, such gaps could widen further over time. Busan is currently pursuing an administrative merger with South Gyeongsang, aiming to complete procedures, including a resident referendum, by 2028. In contrast, Incheon is not part of any administrative merger target area.
Inside and outside local governments, policy support tied to administrative mergers is also cited as a variable. An official at a local government said, "The government is reviewing various incentives, including the transfer of public institutions, for regions pursuing administrative mergers," adding, "Regions without merger discussions or with slow progress may find it hard to receive such benefits."