Thailand’s $20 Billion Urban Bet: Can Secondary Cities Challenge Bangkok’s Economic Dominance?

A World Bank study finds that Bangkok delivers faster economic returns, but large, sustained investment in Thailand’s secondary cities could generate higher long-term growth, lifting GDP per capita by about 12.4% by 2050. For governments, development partners and investors, the key lesson is that scale, targeted investment and long-term commitment—not simply choosing Bangkok over regional cities will determine Thailand’s future urban growth.

A World Bank study has put numbers behind one of Thailand's biggest development choices: whether to keep concentrating investment in Bangkok or build stronger economic centres across the country. Prepared by Putu Sanjiwacika Wibisana and Steven Louis Rubinyi of the World Bank's Urban, Disaster Risk Management, Resilience and Land Global Department and issued through the World Bank's Policy Research Working Paper Series, the research finds that Bangkok remains the stronger option for quick economic returns, while large and sustained investment in secondary cities could produce greater long-term gains by 2050.

The study uses an economic model covering 75 Thai urban centres from 2025 to 2050. It examines Bangkok alongside 11 secondary cities—Chiang Mai, Chon Buri, Hat Yai, Khon Kaen, Lop Buri, Nakhon Pathom, Nakhon Ratchasima, Pattaya, Phuket, Songkhla and Ubon Ratchathani. Researchers assessed how investment could affect productivity, migration, population density, capital, housing, congestion and market access.

Bangkok Wins Early, Secondary Cities Gain Over Time

Three investment strategies were tested using roughly the same overall investment envelope, equivalent to about 2.3 percent of Thailand's projected 2030 urban GDP. The first directs 80 percent toward Bangkok and 20 percent toward secondary cities; the second divides investment equally; and the third sends 80 percent to secondary cities and 20 percent to Bangkok.

Bangkok delivers the fastest initial returns. By 2030, the Bangkok-focused strategy increases GDP per capita by 1.92 percent compared with the no-investment baseline. The balanced strategy generates 1.65 percent and the secondary-city strategy 1.40 percent.

The advantage continues through 2040, when the respective gains reach 6.29 percent, 5.58 percent and 5.32 percent. Even in 2045, Bangkok remains ahead at 8.82 percent.

By 2050, however, the ranking changes. The secondary-city strategy produces a GDP-per-capita gain of about 12.38 percent, compared with 11.62 percent for the Bangkok-focused approach and 10.85 percent for the 50:50 strategy.

The reason is that secondary cities have greater room for agglomeration. Large productivity improvements attract workers and businesses, increasing population density and creating further productivity gains. Bangkok already has a highly concentrated economy, meaning congestion and other costs increasingly limit the benefits of additional density.

A $20 Billion Threshold Could Shape Policy Choices

Perhaps the most important finding for policymakers is that the amount invested matters as much as where it is invested.

The model identifies a tipping point equivalent to roughly US$20 billion–US$21 billion in 2017 purchasing-power-parity terms at the 2030 baseline. Below this level, concentrating resources in Bangkok generally generates stronger returns. Above it, sufficiently large investment in secondary cities can trigger stronger economic effects and eventually outperform the capital.

This finding also challenges the political attraction of dividing resources equally. The 50:50 strategy performs worse than either concentrated alternative across much of the analysis because investment can become too thinly spread to generate strong agglomeration effects.

For governments facing limited budgets, the message is practical: funding every regional city equally may not be the most productive approach. Concentrating investment in a smaller number of promising secondary cities could create stronger growth centres.

The report also highlights a political challenge. Secondary-city investment may take well over a decade to demonstrate its full advantage. Governments therefore need multi-year financing commitments and performance systems that assess long-term progress rather than expecting immediate GDP gains.

Regional Growth Could Reshape Business Opportunities

The biggest differences between the strategies are not in national GDP but in where economic activity takes place.

Under the secondary-city strategy, the combined population of the 11 targeted cities increases from about 3.36 million in the baseline to 5.15 million by 2050—a rise of approximately 53 percent. Their combined GDP jumps from around US$137 billion to US$351 billion, an increase of about 157 percent, while GDP per capita rises approximately 67 percent.

Such a shift could create major opportunities for private investors in housing, industrial property, logistics, transport, retail, utilities, financial services and digital infrastructure. Chon Buri, Chiang Mai, Khon Kaen and Nakhon Ratchasima show particularly strong responses in the model because of their existing scale and connectivity.

But there are risks. Urban centres outside the targeted network lose around 6.9–7.1 percent of GDP and 8.6–8.9 percent of population relative to the baseline as workers and economic activity move toward investment hubs. Governments would therefore need policies to manage the transition in smaller cities, while businesses would need to assess where future labour and consumer demand are likely to concentrate.

Development Partners Need Scale, Patience and Better Targeting

For the World Bank, other multilateral development banks, bilateral agencies and development finance institutions, the study suggests that isolated projects may not be enough to transform regional economies. Creating successful growth poles may require coordinated packages combining transport, urban infrastructure, skills, business development, housing, digital connectivity and institutional strengthening.

The researchers recommend more detailed future analysis of transport networks, fiscal systems, different industries and workers with different skill levels. They also suggest examining specialised development strategies, such as Chiang Mai as a creative-economy centre, Khon Kaen as an advanced manufacturing hub and Hat Yai as a trade and logistics centre.

The study cautions that its figures are modelled estimates rather than forecasts. Financing costs, implementation failures and sector-specific differences are not fully captured.

Its broader message, however, is clear. Thailand does not face a simple choice between Bangkok and the regions. Small budgets and short timelines favour Bangkok; large, sustained programmes can make secondary cities increasingly competitive. For policymakers, development partners and investors, the strategic question is whether Thailand can mobilise enough resources, target them effectively and maintain the commitment long enough to create new economic engines beyond its capital.