At a National Assembly forum on Tuesday, South Korean lawmakers from multiple parties and civic groups proposed taxing unrealized gains on stocks and real estate, sparking a severe market selloff dubbed 'Black Tuesday.' The proposal would treat paper profits as taxable income even before asset sale, redefining wealth taxation. The KOSPI plunged as retail investors feared forced selling to pay annual liabilities. Critics cite the Dutch precedent (36% flat tax on unrealized gains enacted February 2026) warning of innovation stifling and capital flight. Supporters argue it closes tax gaps between wage earners and high-net-worth holders. Legislation faces divided National Assembly approval.

Key facts

• South Korean lawmakers propose taxing unrealized gains on stocks and real estate.
• Market selloff on June 23 dubbed 'Black Tuesday'; KOSPI plunges.
• Investors fear forced selling to pay tax on paper profits.
• Netherlands set precedent with 36% unrealized gains tax in Feb 2026.
• Proposal backed by multiple parties and major trade unions.