What Are ASM and GSM? (Stock Surveillance Explained)
ASM and GSM are surveillance frameworks the exchanges and SEBI use to protect investors from manipulation and excessive speculation. When a stock is placed under them, extra trading restrictions kick in — and it's a signal worth noticing.
ASM — Additional Surveillance Measure
A stock can be put under ASM when it shows unusual activity — sharp price swings, abnormal volumes, or volatility far beyond the norm. ASM brings extra curbs like higher margin requirements, which make it costlier and harder to speculate on the stock, cooling things down.
GSM — Graded Surveillance Measure
GSM targets stocks with weak fundamentals that are nonetheless seeing suspicious price action — a classic setup for manipulation. It applies progressively stricter "grades" of restrictions, which can go as far as allowing trading only periodically with a large deposit, making the stock very hard to trade.
What it means for you
If a stock you're looking at is under ASM or especially GSM, treat it as a loud caution flag — the regulators are signalling unusual or risky behaviour. These are often thinly traded small caps or penny stocks. Always cross-check the company's actual financials and shareholding before going near one.