Additional surveillance measure

A framework under which exchanges place unusual securities under heightened surveillance, applying stricter margin requirements and sometimes restricting trading to a periodic call auction.

Placement is driven by price and volume behaviour rather than by any finding about the company, so it is a market-microstructure flag rather than a fundamental verdict.

For an investor the consequences are practical: higher margins, thinner liquidity and greater difficulty exiting a position.

A stock that has been under surveillance repeatedly deserves an explanation before capital goes near it.