Notably, VIC added 5.66 points, helping the benchmark narrow its losses by nearly 8 points.

Trading on September 19 was marked by strong volatility as the session coincided with ETF portfolio restructuring. At one point, the VN-Index plunged almost 22 points before paring losses to finish down nearly 7 points.
Real estate stocks continued to attract capital inflows and largely held their upward momentum. Several names posted sharp gains. Specifically, QCG hit the ceiling, NVL climbed 5.63 percent, VIC rose 5.66 percent, CEO gained 3.38 percent, KDH surged 2.69 percent, SCR advanced 2.08 percent, DIG rallied 1.45 percent, HDC edged up 1.15 percent, while PDR and DXG each added about 1 percent.
By contrast, the financial sector—especially banking—fell steeply, exerting heavy pressure on the index. STB dropped 3.16 percent, BID 2.45 percent, TCB 1.03 percent, VCB 1.41 percent, HDB 1.63 percent, VIB 1.22 percent, EIB 2.06 percent, and VPB 1.3 percent. Securities stocks also sank, with VIX down 4.86 percent, VND 2.78 percent, VCI 1.5 percent, ORS 1.68 percent, and SSI 1.1 percent.
Consumer and energy stocks also slipped into negative territory, with VNM down 2.52 percent, VHC off 1.73 percent, SAB losing 1.71 percent, BSR falling 3.17 percent, and PVD retreating 1.09 percent.
At the close, the VN-Index slipped 6.56 points, or 0.39 percent, to 1,658.62, with 189 stocks declining, 133 advancing, and 58 treading water. On the Hanoi Exchange, the HNX-Index also retreated 0.68 points, or 0.25 percent, to 276.24, with 94 losers, 62 gainers, and 55 unchanged stocks.
Liquidity improved, with total trading value on HOSE reaching about VND29.2 trillion, up VND1.4 trillion from the previous session. Including HNX, combined liquidity approached VND30.7 trillion, an increase of VND600 billion.
Foreign investors extended their heavy net-selling streak on HOSE, unloading nearly VND2.82 trillion, largely concentrated in blue chips. The three most heavily sold stocks were VHM (VND468 billion), SSI (nearly VND297 billion), and STB (nearly VND283 billion).