FTSE index reshuffle prompts special monitoring for suspected market manipulation and insider trading

Vietnam’s stock market regulator is creating a separate surveillance track for FTSE Russell index rebalancing, targeting trades that could manipulate prices or exploit inside information.

The Vietnam Exchange has issued a regulation that takes effect immediately for shares listed on the Ho Chi Minh City Stock Exchange, or HOSE. The enhanced monitoring will run from before FTSE Russell sets its input data until five trading sessions after the new portfolio becomes effective.

The monitoring will operate in three stages. The first begins on the session before FTSE Russell’s data cut-off and continues until the session before the results are announced. The second runs from the announcement date until the session before the new portfolio takes effect. The third begins when the new portfolio becomes effective and lasts for five more sessions.

The first group subject to enhanced scrutiny includes stocks that could be added to or removed from the index, starting from the data cut-off date. The second covers stocks officially listed by FTSE Russell for addition or removal. HOSE will track accounts and groups of accounts showing signs of influencing prices or liquidity, as well as possible insider trading. A separate monitoring group will focus on accounts that affect closing prices on the session before the index changes take effect. For the September review, that session is Sept. 18.

HOSE will develop and issue the detailed monitoring process after approval from Vietnam Exchange. It must set the parameters for each monitoring criterion and seek feedback from the exchange before applying them. Securities companies may be required to provide information and documents explaining suspicious trades, which must be reported to Vietnam’s State Securities Commission and Vietnam Exchange.

The regulation comes three weeks before Vietnam’s planned market reclassification. FTSE Russell has said Vietnam will move from a frontier market to a secondary emerging market, effective from the start of trading on Sept. 21, 2026.