SINGAPORE (BLOOMBERG) - Singapore-based start-up Trax is acquiring US rewards app Shopkick, adding a customer-tracking service to its growing stable of retail technology.

California-based Shopkick lets shoppers earn rewards and gift cards by browsing online offers, watching videos, walking into stores or scanning product barcodes on shelves. Trax didn't disclose how much it's paying but seller SK Telecom Co acquired the outfit for US$200 million (S$270.7 million) in 2014, the Wall Street Journal has reported.

Shopkick's programs help provide data and insights into customer behavior and loyalty for clients from EBay and General Electric to Lego and Unilever. "Bringing together shelf and shopper data will deliver new and powerful insights to consumer-packaged-goods brands and retailers," Trax chief executive officer Joel Bar-El said in a statement.

The transaction comes as Trax finalizes a deal to raise US$100 million at a pre-money valuation of about US$1.1 billion, that could make it the second most valuable start-up in Singapore, behind only Grab. The round was aimed at financing acquisitions, including of LenzTech Co, a Beijing computer vision start-up it recently purchased. Trax is also in advanced talks to buy a European competitor, Bar-El has said.

The Singapore startup plans an initial public offering in 18 to 24 months and it's in talks with the Singapore Exchange for a potential dual listing after the local bourse approached the company, the CEO said in an interview last month.

Bar-El and partner Dror Feldheim co-founded Trax in Singapore in 2010. The firm works with retailers and brands in more than 50 countries and counts New York-based private equity firm Warburg Pincus, Chinese private equity firm Boyu Capital and Singapore's sovereign wealth fund GIC among its shareholders.