The 2011 floods were one of Thailand’s worst on record, affecting much of the country, especially the Central and Northern regions, where flooding persisted for several months, according to the Water Resources Information Institute.
The institute noted that Bangkok and nearby areas suffered their worst flooding since the major flood of 1942.
The floods caused extensive damage to agriculture, industry, the economy and society, with effects rippling across many other sectors, prompting the organisation to call the event ‘Thailand’s Great Flood’.
A 2013 article in Asia Insurance Review also underscored the scale of the disaster, noting that Thailand, previously classified as a non-CAT country, was reclassified after the floods. It added that reinsurers worldwide then moved to “reclassify all countries as catastrophe prone”.
Factors behind the flood
Thailand is no stranger to natural catastrophes, with the World Bank even pointing out in its ‘Rapid Assessment for Resilient Recovery and Reconstruction Planning’ report, published in 2012, that “flooding occurs every year in the Chao Phraya River Basin”.
“Tropical storm cycles come from the east through Laos and Vietnam and touchdown in the northern parts of the country where water collects and flows downstream into the basin,” the report explained.
As a result, the 2011 floods were not the first to cause widespread damage. In fact, the report highlighted the 1942 flood in Ayutthaya, which reached 5.51m and inundated Bangkok for two months. The country was then inundated again in 1983, this time for five months, when a cyclone hit.
Yet another flood in 1995, precipitated by unprecedented rainfall left the largest recorded area of 5,400m3 underwater.
More recently, floods occurred again in the country in November 2025. News platform The Nation Thailand, citing the Department of Disaster Prevention and Mitigation (DDPM), reported that 10 provinces were affected and 980,000 families (approximately 2m people) were impacted. It also estimated daily trade and tourism losses at up to THB1.5bn ($45.96m). News agency Xinhua reported 33 fatalities.
What made this flood different?
So, what led Swiss Re Head Property UW EMEA Jens Mehlhorn to describe the 2011 floods as “entirely different” in a 2021 article?
One of the factors Mr Mehlhorn listed was the floods helped push flood risk to the top of Asia’s policy and business agenda. The other was the acceleration of efforts to strengthen infrastructure and risk management.
Moreover, according to the World Bank’s report, more than 680 deaths were recorded (the Water Resources Information Institute cited the DDPM’s 1,026 fatalities), and 13m people were affected.
“Caused by excessive and continuous rainfall from successive, powerful monsoons and subsequent, numerous dam breaches, the floods inundated more than 6m hectares of land in 66 of the country’s 77 provinces,” the report also stated.
AM Best also compared the relatively low insured losses of this event to that of Japan’s earthquake and tsunami in March 2011, in a 2012 report titled ‘Flood Losses Prompt Key Changes in Thai Insurance Industry’, attributing it to “a low rate of insurance adoption”.
Damages and losses
Of the economic damages and losses due to the floods, the World Bank estimated in its report that the manufacturing sector bore roughly 70% of the total, and the private sector bore approximately 90% of the loss.
Rehabilitation and reconstruction were also estimated at THB1.5tn, as of 2012. Additionally, the report stated that the nation’s “commercial financial institutions and the government’s specialised financial institutions require approximately THB411bnin loans for rehabilitation and reconstruction”.
Mr Mehlhorn in his 2021 article also called it the “costliest flood event on record for the global insurance industry”, with total economic losses of $46bn in 2011 ($55bn in 2021) and final insured losses of $15bn.
AM Best also compared the relatively low insured losses of this event to that of Japan’s earthquake and tsunami in March 2011, in a 2012 report titled ‘Flood Losses Prompt Key Changes in Thai Insurance Industry’, attributing it to “a low rate of insurance adoption”.
Lastly, the World Bank’s report noted that although the 2011 flood area was smaller than the area affected in 1995, the impact it had on life and the cost of damage was unprecedented.
“These factors contributed to the 2011 floods registering on the magnitude of roughly a once in every 50- or 100-years event,” the report added.
Impact on the (re)insurance industry
Immediate impact
According to AM Best’s report, in 2012, flood coverage was separated from industrial all-risk policies.
“Flood policy premiums are expected to double or triple from previous levels, while the renewal and expansion of excess-of-loss protection has driven rate increases ranging from 500% to 1,000%,” the report added.
“Policy limitations on coverage amounts available for specific types of loss likely will be cut to 10%- 20% of the sum insured. Deductibles of 10% are likely to follow.”
Demand for insurance also experienced a sharp spike, leading to temporary cancellations of risk protection by insurers who had yet to finalise new policies on coverage.
“The hardening of rates, coupled with contracted capacity, could prompt more multinational firms to self-insure through captives,” the report also stated.
On a regulatory note, the Thai government and the Office of Insurance Commission (OIC) faced two challenges: guaranteeing the population’s access to insurance while protecting the Thai market’s desirability.
“Most reinsurance firms are now hesitant to renew flood-related contracts for Thai companies until the government develops a clear flood-prevention plan,” the report said, noting that a government plan for water management and flood prevention was met with scepticism.
The report also pointed out that some insurers remained “undecided on whether to continue offering flood coverage”, as the monsoon season after the floods was expected in four months.
“The Thai government would need to convince reinsurers that the risk in Thailand is both manageable and profitable,” said the report.
As such, the OIC raised the minimum capital adequacy ratio requirement for insurers to 140% from 125%, in January 2013.
Complex CBI claims
Other than the reclassification of Thailand to a catastrophe-prone country, the (re)insurance industry also took “significant time to reconcile the true impact of the floods because of a general lack of data on Thai exposures, the length and magnitude of the floods and the complexity of business interruption and contingent business interruption (CBI) claims”, the AM Best report stated.
In 2012, policyholders and insurers found it difficult to accurately estimate income lost to production shutdowns, incurred costs due to supply-chain disruptions and damage to property and equipment.
Additionally, due to the impact on manufacturing in Thailand’s industrial estates, a major uncertainty involved the calculation of CBI losses, the report continued.
The report listed some of these uncertainties, including:
- Insured limitations on ability to make CBI claims.
- Insurers perhaps encountering reinstatement issues and facing problems on first-loss limits from firms with multiple locations, as dates of damage vary for different industrial estates.
- Event limits were not always specified in Thai insurance contracts.
- Classifying the floods as multiple events perhaps raised costs for (re)insurers involved.
As many impacted companies had moved to Thailand to mitigate losses in the wake of the March 2011 earthquake and tsunami in Japan, complex causation and adjustment issues were brought about.
Protection gaps exposed
CBI extensions failed policyholders
In a 2025 article, insurance and risk legal business Wotton Kearney spelt out some coverage gaps the 2011 floods exposed in Thailand, most notably what was covered by CBI extensions.
For instance, they mentioned that “many Thai commercial policies were written with primary property damage and business interruption cover on an all-risks basis, providing broad protection for direct losses”.
“However, CBI extensions covering suppliers, customers and supply chain disruption were typically written on a limited perils basis, covering only fire, lightning and explosion,” the article added.
Thus, when the floods caused widespread supply chain disruption across Thailand, the business highlighted that “policyholders discovered that their CBI extensions provided little to no coverage for flood-related supply chain losses”.
“Facilities that had comprehensive flood coverage for direct damage to their own premises found themselves entirely uninsured for business interruption losses arising from flood damage at suppliers’ or customers’ locations,” said the article.
These losses were compounded by the interconnected nature of manufacturing in Thailand, where supply chain disruptions often exceed direct physical damage losses.
“The limited perils restriction in CBI extensions meant that policyholders faced substantial uninsured losses despite holding what they believed to be comprehensive commercial insurance,” the article added.
Secondly, the article mentioned the restricted indemnity periods for CBI extensions, which were brought to light by the prolonged period of flooding in 2011 – the World Bank noted that the event lasted from July to December 2011 in its report.
“CBI extensions such as loss of attraction, and prevention of access typically contained express limitations on the duration of coverage, commonly 30 days from the date of damage,” the article said.
Flood risk mitigation strategy overwhelmed
According to a report brokerage firm Guy Carpenter published 2012, ‘Thailand Flood 2011: One Year Retrospective’ report, flood mitigation strategies in the Chao Phraya Basin include both structural and non-structural measures.
“However, in many cases structural solutions failed: Flood walls broke after prolonged flood period in many areas including the ancient city of Ayutthaya, and some industrial estates,” said the report.
“For example, part of the embankment of the Hi Tech Industrial Estate located north of Bangkok broke as leakage weakened its structure and emergency reinforcement failed.”
Population exposure to flood risk
While Guy Carpenter conceded that heavy rainfall may have contributed to the floods, the brokerage firm also pointed out several underlying factors that left the country exposed to risk.
For instance, the report cited the increase of population exposure, as the region had rapidly industrialised and urbanised. As such, “exposure of population and economic assets has increased considerably”, the report showed.
In fact, a 2008 paper by the Organisation for Economic Co-operation and Development, titled ‘Ranking Port Cities with High Exposure and Vulnerability to Climate Extremes: Exposure Estimates’, had already ranked Bangkok as one of the top 10 cities in terms of population exposure to the combined effects of climate change (sea-level rise and increased storminess), subsidence and urbanisation by the 2070s.
Lessons learned…
In the wake of the 2011 floods, Thailand introduced a series of disaster risk finance mechanisms and instruments.
For instance, a government-subsidised crop insurance scheme for rice and maize farmers was introduced as a risk transfer mechanism, according to a report titled ‘Inclusive insurance and risk financing in Thailand: Snapshot and way forward 2023’, by the United Nations Development Programme (UNDP) and Insurance and Risk Finance Facility.
A microinsurance ‘top-up’ is also available on top of the government programme, that covers, among other things, flood, drought, hail and pests. However, it should also be noted that the scheme only covers two crops, leaving what the UNDP described as “much of the agriculture base” unprotected.
“In 2021, the disaster relief programme compensated around 33% of costs for rice farmers, and the insurance top-up covered approximately an additional 33%,” said the report.
The report also found that, as of 2020, 72% of rice cultivation and 28% of maize cultivation were insured.
A National Catastrophe Insurance Fund was also established after the floods, the report revealed. It has since been terminated (in 2017) “due to better reinsurance options and lack of additional major disasters”.
This fund, according to AM Best’s report, covered up to $16.2bn in losses, as of 2012.
“This potential risk-sharing scheme between the Thai government and 67 non-life insurance companies, if successful, would be the biggest excess-of-loss property CAT treaty in the world,” said the report.
“These funds would help cover the massive disaster costs while helping insurers to continue underwriting risk.”
Despite this, AM Best also expected the scheme to be criticised “because of Thailand’s small reinsurance premium base”.
… or were they?
Despite the progressions stated above, the UNDP also noted in its report that “coordinated insurance awareness and information efforts are very limited”.
Moreover, the organisation noted that data on disasters and losses “is fragmented and difficult to access”, even as Thailand is starting to promote the development of a disaster prevention and mitigation plan at both national and sub-national levels.
It also highlighted the lack of formal procedures to estimate disaster risk and level of budget needed for emergencies and disaster management.
“The risk financing strategy in the country is highly reliant on risk retention, where contingent budgets are the main financing resources for post-disaster relief and recovery,” the report also stated, noting that the nation could explore innovative risk transfer products, such as CAT bonds or parametric insurance. A