Ending up with $100 notes when you withdraw cash at a DBS ATM is often a matter of location.
The bank said that some ATMs are more likely than others to dispense such notes while big withdrawals will also tend to yield more bills of larger denominations.
DBS' remarks came after Straits Times reader Phua Peng Hwee wrote to the ST Forum page last month, noting that he got more $100 notes than usual from an ATM he frequently used at Peninsula Plaza.
Mr Phua said he withdrew $1,000 and received eight $100 notes and four $50 notes, instead of the usual 20 $50 notes. He added that it was generally more difficult to use $100 notes in daily transactions.
A DBS spokesman said the bank was constantly updating the dispensing logic of its ATMs, relying on past customer withdrawal patterns to determine what proportion of note denominations are dispensed.
In Resorts World Sentosa, for example, where customers tend to withdraw large amounts, the ATMs were stocked with more $100 notes, she added.
An ATM might also have to dispense $100 notes if it is running low on smaller denomination ones.
Mr Phua told The Straits Times that he was "happy" that DBS had told him which ATMs near his home dispensed more $10 and $50 notes.
The bank also suggested that he withdraw smaller amounts to avoid ending up with $100 notes, but he said this would involve making multiple withdrawals and would hold up other customers in the queue.
"It would be very inconsiderate for me to take $290, put my card back in again, take another $290, I must be mindful of people behind me, right?" he added.
A Citibank spokesman said its ATMs have started dispensing more $100 notes, partly because its customers had increased purchasing power and so were withdrawing larger amounts.
Standard Chartered said that less than 10 per cent of its 31 ATMs dispense $100 notes. It reduced the number after customers said smaller denominations were more convenient.
Only about 5 per cent of UOB's 600-plus ATMs dispense $100 notes. These are mostly found at a handful of locations, such as commercial hubs and malls in Orchard Road, a UOB spokesman said.
OCBC said that none of its ATMs dispense $100 notes as $50 notes were more convenient.