Re-commerce, handshake and circular are among the ways to describe a used-goods economy that has taken off thanks to online tools promising to make transactions easy and safe.

Sadly, the new apps are the focus of a new cybercrime battle against scammers up to some old tricks. Hong Kong police showcased scams involving the second-hand sales platform Carousell.

The app was involved in 644 cases tallying up HK$36 million (US$4.63 million) in losses over the first 10 months of 2024.

The force’s cybersecurity and technology crime bureau said online shopping scams between January and October cost victims more than double what was lost over the same period in 2023.

Losses increased with multiple large transactions using cryptocurrency. In the largest single case, a 32-year-old accountant lost nearly HK$900,000.

Swindlers used fake screengrabs that mimicked Carousell’s payment function within the app. Investigators said the fake buyers tried to build trust and “express interest” in purchasing an advertised item, then asked for a seller’s email address.