The State Post Bureau has launched an investigation into Yunda Express over significant safety management loopholes that allowed fraudulent promotional materials to infiltrate its delivery system, leading to substantial financial losses for victims.

The probe follows reports that some franchisees of Yunda Express, a Shanghai-based courier company, used its services to distribute scam-related promotional materials.

In response, Yunda Express issued a statement on Thursday on the Shenzhen Stock Exchange's website, pledging to cooperate with regulators. The company said it had formed a special task force to conduct an internal investigation and vowed to strengthen oversight of its franchise operations. It also plans to enhance inspection procedures, intensify franchisee training and improve its ability to detect scam-related parcels.

The investigation was likely triggered by reports of fraudulent "prizewinning" materials sent through courier services, including Yunda. Consumers have reported receiving small unsolicited packages containing gifts and QR codes promising cashback rewards, only to be drawn into scams.

In one case highlighted by the Supreme People's Procuratorate on March 13, a woman in Jiangxi province lost more than 190,000 yuan ($26,400) after scanning a QR code in a package offering a 20-yuan voucher. She was instructed to download an app and interact with customer service representatives, who deceived her into transferring money.

Authorities in Sichuan province seized more than 20,000 fraudulent courier packages in early March, retrieving more than 800 parcels linked to similar scams. Police said scammers used leaflets inside the packages to lure victims into fraudulent schemes.

The probe into Yunda Express comes amid a broader crackdown on courier fraud, which has sparked consumer complaints over privacy breaches and package security.

Zhao Xiaomin, a logistics expert, told National Business Daily that authorities may intensify efforts to tackle fraud in the delivery industry, citing recent discussions on data security at China's top legislative and political advisory meetings.

On Tuesday, the Ministry of Public Security also disclosed cases of collusion in the courier sector, further underscoring regulatory concerns.

"With growing scrutiny over crimes involving personal data, courier companies must remain vigilant, enhance security management and protect user information," Zhao said.

Bao-Ding Yurui, a lecturer at the Renmin University of China, warned that companies failing to comply with security regulations risk penalties, including business suspensions or loss of operating permits.