South Korean companies and securities firms reported sharply stronger second-quarter 2026 results, as artificial-intelligence investment supported semiconductor demand and rising equity markets lifted trading and investment income. Revenue at 4,260 externally audited companies rose 26.7% year on year, while the aggregate operating margin reached a record 16.9%. Combined net profit at 61 domestic securities firms rose 82.1% from a year earlier and 20% from the preceding quarter to 5.1914 trillion won, supported by stronger brokerage commissions, asset-management and investment-banking fees, and proprietary trading gains. Korea Exchange trading value climbed 59.9% quarter on quarter to 4,438 trillion won, while the sector's return on equity rose 0.6 percentage point to 4.9%. The Financial Supervisory Service said it will strengthen inspections of firms' profitability and financial soundness as market volatility risks increase. Third-quarter securities-sector operating-profit consensus stands at 2.1895 trillion won, 45.6% below the second-quarter estimate, after average daily stock-market trading value declined 35.2%.