Straits Times Index: Will MERS cause STI to do a SARS?

On 20 May, South Korea reported the first case of MERS in the country and since then it has spread throughout Asia with Thailand being the latest country to be affected. Singapore’s Lee Hsien Loong has also warned that it is inevitable that MERS “will reach our shores”.

To see if there are any clues how the stock market has and will perform in a period of highly infectious disease, I have in the above chart, superimposed the STI on the corresponding trading day that Singapore reported its first SARScase (1 March 2003) with the trading day when South Korea reported its first MERS case (20 May 2015). Based on 2003 historical trends, I have projected that period’s performance onto the closing STI on 19 June 2015 to create a forecast.

For the 60 trading days before MERS was reported in South Korea, the STI performed in a volatile and mostly positive manner. When news of MERS in South Korea broke out, the index was rather unmoved but has been on a downwards trend since then.

For the corresponding period in 2003, the STI was similarly volatile but in a negative manner. When SARS broke out in Singapore, the index suffered a same day plunge but quickly recovered. It then fell for the next 20 trading days before staging a broad market recovery.

Judging by the immediate trading days before SARS, should MERS hit Singapore, we can expect the STI to plunge rather sharply. However, the market is expected to rebound short-term. However, unlike in 2003, I caution against expecting a longer term recovery because that 2003 period coincided with one of the greatest secular bull markets of our time.

Therefore, the verdict therefore is that you should look at the bigger picture. MERS will benefit day-traders as it provide the catalyst for short-term massive fluctuations as fear initially permeates and sets in. After a while, this information should be priced into the market, with broader factors dictating its longer-term movement.