On the Ho Chi Minh Stock Exchange, on which the VN-Index is based, 190 stocks lost and 129 gained. Liquidity rose slightly above the November average to VND3.68 trillion ($159.89 million).

The VN30-Index, which represents Vietnam’s 30 biggest market cap stocks, fell 0.73 percent this session, with 17 losing and eight gaining.

In particular, MSN shares of food conglomerate Masan Group plunged 7 percent, its price floor, making it the biggest loser on the VN30. Over Tuesday’s session, 2.27 million MSN shares had changed hands, up sharply from 273,550 shares the previous session.

The stock had plummeted following an announcement by Vietnam’s biggest private conglomerate Vingroup Tuesday morning, saying it had reached a deal with Masan to merge their retail subsidiaries to form a new company, which will control over 2,600 supermarkets and convenience stores nationwide.

Vingroup’s VIC shares, on the other hand, saw no change in price. VRE shares of Vingroup’s retail arm Vincom retail also remained at opening price, while VHM of real estate arm Vinhomes shed only 0.1 percent.

The biggest losers on the VN30 this session following Masan Group were VNM of Vietnam’s biggest dairy company Vinamilk, down 1.9 percent, BVH of insurance giant Bao Viet, down 1.8 percent, and VCB of major state-owned lender Vietcombank, down 1.5 percent.

In the opposite direction, PNJ of Phu Nhuan Jewelry, MWG of electronics retail giant Mobile World, and HPG of steelmaking giant Hoa Phat Group gained 1 percent, 0.8 percent and 0.5 percent respectively.

Foreign investors were net sellers this session, offloading a net VND230 billion ($10 million) worth of shares, with selling pressure mainly on blue chip stocks like MSN of Masan Group, VNM of Vinamilk, and VHM of Vinhomes.

Meawhile, the HNX-Index for stocks on the Hanoi Stock Exchange, Vietnam’s second main bourse for small and mid-cap stocks, rose 0.17 percent, while the UPCoM-Index for the Unlisted Public Companies closed 0.02 percent higher.