Several businesses will close on Sunday as a mark of respect for former Prime Minister Lee Kuan Yew, whose funeral will be held that afternoon.
Others will drop their sales events and freeze operations from 2pm - the time the service begins.
Department stores Tangs, which has outlets in Vivocity and Orchard, and Metro, with five branches here, will close for all of Sunday - their second-busiest day of the week.
So will Mothercare's 14 outlets, accessory chain Accessorize's seven outlets, two Island Shop boutiques, apparel store Cache Cache's two outlets, all Club 21 free-standing outlets, and children's clothes store King Kow.
The 48-outlet Ya Kun Kaya Toast will halt operations from 2pm to 4pm, and three retailers in The Shoppes at Marina Bay Sands have postponed their events, including Cath Kidston's island-wide marketing campaign and the official store opening event of Kate Spade New York.
Ms Sherri Lim, Tangs' vice-president of store operations and human resources, said the decision to close is "a gesture of respect".
Tangs has about 1,000 employees. Sunday sales contribute about 15 per cent of its weekly revenue. "The closure will also enable our staff to pay their final respects to Mr Lee Kuan Yew," she said.
Metro's advertising and promotions manager Veronica Lee said the decision to shut was to give its 500 staff members "a day for silence and reflection".
Singapore Polytechnic senior retail lecturer Sarah Lim estimates the closure will cost each department store more than $200,000.
Shutting on Sunday will cost King Kow, which has just one outlet in Paragon, between $3,000 and $5,000. Its 10 employees will head to Parliament House on Saturday night, where Mr Lee's body is lying in state.
"If we close on Sunday, staff don't have to rush home - the queue may be very long," said company spokesman Sally Maisarah, adding that weekends make up 60 per cent of total weekly takings. "We still have to pay rent. We lose money, but we feel we must close as a mark of respect for our founder."
The majority of businesses, however, will remain open, including major retailer Courts and department stores Robinsons and Takashimaya.
It is also business as usual at supermarkets such as Sheng Siong and NTUC FairPrice.
Malls contacted by The Straits Times said that no other tenants have informed them about shutting on Sunday and the Singapore Retailers Association is not aware of other closures.
Takashimaya said it decided to remain open because "we still have tourists coming in and we want to take care of our customers."