Singapore's central bank on Friday introduced rules to ensure that a property buyer's monthly payments do not exceed 60 percent of his income, a move aimed at cooling the housing market and ensuring investors are not caught out by a rise in interest rates.
"The TDSR (total debt servicing ratio) will apply to loans for the purchase of all types of property, loans secured on property, and the re-financing of all such loans," the Monetary Authority of Singapore (MAS) said in a statement.
The new requirement, which takes effect on Saturday, will also help strengthen credit underwriting practices by banks and encourage financial prudence among borrowers, MAS added.
Singapore has been trying to keep a lid on property prices due to low interest rates caused by quantitative easing adopted by Western central banks.
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The flush liquidity could reverse in coming months, however, amid signs that the U.S. Federal Reserve is preparing to slow down its bond buying program.
"The MAS is probably worried that in the environment of low-interest rates, people are overly gearing themselves up to pay for property," said Kenneth Ng, head of CIMB Research in Singapore.
Singapore's 10-year bond yield has risen by more than a percentage point since the start of the year to around 2.5 percent currently, from around 1.3 percent at the end of 2012, following the upward trend in U.S. yields.
But mortgage rates, which in the AAA-rated city-state are tied to short-term interest rates, have only edged up slightly, with the three-month interbank rate little changed from the start of the year at around 0.4 percent.
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Barclays, in a recent report, said Singapore property prices were vulnerable to a sharp rate increase after three years of super-low interest rates when private home prices rose by around 60 percent.
Should mortgage rates rise by 200 basis points within a short period, private residential prices in the city-state could fall by up to a quarter, it said.
Singapore has rules regulating the maximum amount of money banks can lend based on the value of the property.
The new requirements, which tie the loan quantum to income levels, will make it harder for property buyers to avoid additional stamp duty on purchases of second homes since they cannot use a family member's name for subsequent purchases.