Which Singapore bank showed the most improvement in its capital ratio?

UOB beat its peers in terms of capitalisation.

The three Singapore banks' capitalisation remained strong in Q3 2017, led by UOB which improved its fully loaded CET1 capital ratio. Moody's said OCBC's ratio was flat, whilst DBS's decreased marginally QoQ. The capital ratios are supported by retained earnings and issuance of new equity shares through scrip dividend schemes.

Here's more from Moody's:

Also, UOB's and OCBC's capital ratios got a boost from a decrease in market RWAs in Q3 2017, following MAS's amendment to capital requirements for structural FX risk. DBS did not benefit as much.

The impact of SFRS 109 on DBS's fully-loaded CET1 ratio will be neutral, because the bank has already channeled its excess general provisions into specific provisions. As for OCBC and UOB, they have not said what their preference is, but their CET1 ratios will be stable if they go for the same option as DBS.

Loan growth strengthened in Q3 2017, driven by increases in trade loans and loans for cross-border investments, as well as in domestic mortgages, amid healthier economic and trade activity in Singapore and Asia.