Wall Street's reliance on leveraged tax-aware long/short strategies has driven a surge in borrowing, with Charles Schwab reporting record margin loan balances of $187.9 billion in the third quarter of 2026, including $60.7 billion tied to these strategies. This increase reflects a market-wide trend where margin debt hit a record $1.502 trillion in June 2026.

This surge in leveraged borrowing raises concerns about potential market instability and systemic risks. Historically, similar rapid increases in margin debt have preceded significant market downturns, including the dot-com bust and the 2008 financial crisis. Regulators and major brokerages are now scrutinizing these strategies.

Records Show Borrowing Increase

Market-wide margin debt reached a record $1.502 trillion in June 2026, marking a 77% rise over 14 months from approximately $850.6 billion in April 2025. Charles Schwab's client margin loan balances reached $187.9 billion by September 30, 2026, which is a company record. Approximately $60.7 billion of this amount came from long/short strategies. These tax-aware long/short strategies use borrowing to increase market exposure for tax-loss harvesting. The goal is to magnify opportunities to generate losses for tax purposes, often by adding leverage to an existing portfolio to buy more positions. Short positions can create losses for tax purposes in both rising and falling markets. These strategies have attracted more than $170 billion in assets.

Brokerages and Regulators React

Major brokerages have begun implementing restrictions on these accounts. Fidelity started limiting new accounts for these strategies in February 2026. Charles Schwab introduced its own restrictions, including increasing the minimum investment for certain new accounts from $1 million to $10 million. Schwab also stopped new client enrollments and additional funding in portfolio margin accounts.

Treasury officials have cautioned against "aggressive planning" involving investment products designed to generate tax losses. Treasury has expressed concerns about products that provide significant tax benefits, including ordinary tax losses, and is actively reviewing these strategies. Kevin Salinger, deputy assistant secretary for tax policy at the Treasury, warned investors about offers that seem "unusually attractive" during a Wall Street Tax Association seminar.

Potential Risks

The use of leverage and short selling in these strategies introduces several risks, including market fluctuations, borrowing costs, and liquidity constraints. Some advisors question whether these strategies have become large enough to create systemic market risk. Experienced managers are needed to navigate the complexities and costs of leveraging and shorting to amplify tax losses.

What we could not confirm

The Treasury has not announced new rules or guidance regarding these tax-aware investment strategies. It is not clear what specific actions the Treasury might take following its review of these strategies.