PNJ Diamond Scandal: Subsidiary Head Arrested, Market Cap Plunges 6,000 Billion VND

Overview

The head of PNJ’s diamond appraisal subsidiary, P-Lab, was arrested for smuggling and falsifying GIA certificates, triggering a crisis of confidence in Vietnam’s diamond market. PNJ’s market capitalization plunged over 6,000 billion VND (approx. 240 million USD) in one week, with the stock hitting the floor repeatedly. The scandal has exposed deep-seated issues in the diamond retail sector, including lack of transparency and weak consumer protection.

Key Facts

• Mr. Dang Ngoc Thao, Director of P-Lab (PNJ’s diamond appraisal subsidiary), was arrested for smuggling and falsifying GIA certificates.
• PNJ’s market cap lost over 6,000 billion VND (approx. 240 million USD) in one week following the arrest.
• PNJ stock closed at 46,600 VND on July 10, 2026, down 6.80% with volume of 10,169,700 shares.
• The scandal involves 28,000 smuggled diamonds with altered GIA serial numbers and re-issued P-Lab certificates.
• PNJ management stated the company is not involved in the 28,000 smuggled diamonds and only imports diamonds through official channels from Thailand and Hong Kong.
• The arrest has triggered a wave of consumers sending diamonds for re-certification and attempting to sell them back.
• Vietnam lacks a centralized diamond exchange or unified pricing mechanism, exacerbating transparency issues.

What Happened

On an unspecified date in mid-2026, Mr. Dang Ngoc Thao, Director of P-Lab (a subsidiary of PNJ), was arrested by authorities for smuggling and falsifying GIA certificates. According to the investigation, Thao colluded with others to purchase diamonds with specifications differing from their GIA certificates at lower prices, smuggled them into Vietnam, then ground off the original GIA serial numbers and re-engraved them with P-Lab codes. He then issued new P-Lab certificates for these diamonds and sold them to customers for profit.

The arrest came amid growing consumer distrust in the diamond market, fueled by social media influencers sharing negative experiences about diamond quality and origin. The scandal immediately triggered a rush of consumers seeking re-certification and resale, further pressuring the market.

Market Context

PNJ, listed on HOSE, has been a blue-chip retail stock in Vietnam. Prior to the scandal, PNJ had a market cap of approximately 30,000 billion VND. The stock has fallen sharply, closing at 46,600 VND on July 10, 2026, down 6.80% with heavy volume. The broader retail sector has also been affected, though PNJ is the most impacted. The scandal has raised concerns about corporate governance and the integrity of PNJ’s appraisal business, which was a key differentiator for the company.

Strategic Significance

The scandal strikes at the heart of PNJ’s brand value, which relied heavily on trust in its diamond certification. P-Lab was positioned as a trusted appraiser, and its misuse undermines PNJ’s competitive advantage. Long-term, PNJ must rebuild consumer confidence through independent audits, enhanced transparency, and possibly third-party certification. The incident also highlights systemic risks in Vietnam’s diamond market, including lack of regulation and consumer protection, which could lead to stricter oversight. For investors, the key question is whether PNJ can contain reputational damage and restore sales, particularly in high-margin diamond jewelry.

What to Watch

• PNJ’s Q2 2026 earnings release for impact on revenue and profit from diamond sales.
• Any regulatory actions or new requirements for diamond certification and import controls.
• PNJ’s response strategy: potential changes in management, independent audits, or new certification partnerships.
• Consumer sentiment indicators, such as foot traffic in PNJ stores and resale market activity.
• Foreign investor flows into PNJ stock, as foreign ownership is near the 49% limit and selling pressure may increase.