LONDON, April 4 (Reuters) - Global securities watchdog

IOSCO on Thursday proposed detailed guidance on how regulators

should supervise stock exchanges more closely to negate risks

from changes in business practices.

"These may give rise to potential risks and challenges

concerning the regulatory functions and responsibilities of

exchanges, as well as supervisory issues," IOSCO, which

comprises securities regulators from across the world, said in a

report.