<p>Binding margin constraints can affect asset prices and trading activity, yet their im- pact in retail-dominated emerging markets remains insufficiently understood. This paper examines stock-level margin eligibility removals (“margin cuts”) on the Ho Chi Minh Stock Exchange during 2020–2025. Using a matched difference-in-differences design that pairs margin-cut stocks with ob- servationally similar margin-eligible peers, the analysis isolates the effect of security-level funding shocks on prices and trading activity. The results show that margin cut announcements are followed by a sharp and persistent decline in stock prices, with treated stocks underperforming matched con- trols by approximately 5% points over the subsequent 30 trading days and exhibiting no evidence of mean reversion. By contrast, trading activity does not contract after margin cuts and instead remains elevated over an extended horizon. Although a mild pre-announcement return drift suggests that some information related to impending margin cuts may be partially anticipated by the market, this effect is economically small relative to the post-announcement price adjustment and does not drive the persistence of the response. The findings indicate that margin eligibility removals primarily operate through funding-constraint and deleveraging mechanisms, while infor- mation effects play a secondary role in shaping market dynamics.</p>