SHANGHAI, June 10 (Reuters) - China’s top banking and insurance regulator Guo Shuqing said banks should actively guard against the rebound in non-performing loans. Investors should also be aware of potential investment losses on financial derivative products, and rising Ponzi schemes, Guo told a financial forum in Shanghai via a video message. The regulator will also resolutely clean up illegal security issuance activities and fend off the pick-up in shadow banking activities, Guo added. (Reporting by Andrew Galbraith in Shanghai; Writing by Cheng Leng in Beijing; Editing by Jacqueline Wong) Our Standards: The Thomson Reuters Trust Principles.