What Is the Volcker Rule?
The Volcker Rule is Section 619 of the 2010 Dodd-Frank Act, born from Paul Volcker's argument that institutions backed by deposit insurance and the Fed's safety net should not gamble for their own account. Regulators finalized the rule in December 2013 and full compliance took effect in July 2015, ending an era in which banks ran internal trading books that functioned like in-house hedge funds.
The rule applies to banking entities, essentially any firm with access to federal deposit insurance along with its affiliates. Beyond the trading ban, it limits a bank's investment in any single covered fund to 3% of that fund's ownership interests and caps aggregate covered-fund investments at 3% of the bank's Tier 1 capital.
How the Rule Works in Practice
Distinguishing banned proprietary trading from permitted activity is the rule's central challenge. Banks may still make markets for clients, underwrite securities, hedge their own risks, and trade US government obligations, and each exemption carries compliance requirements designed to prove the activity serves clients rather than the bank's speculative appetite.
In practice, trading desks must document that inventory is sized to reasonably expected near-term customer demand rather than to a directional view. Regulators simplified the framework in 2019 and 2020, easing documentation burdens for banks with smaller trading books, though the core prohibition remains intact.
Why the Volcker Rule Matters
The rule redrew Wall Street's map. Major banks shut down or spun off proprietary trading units, and many star traders launched or joined hedge funds, accelerating the buy side's rise as the destination for trading talent and shifting risk-taking outside the regulated banking system.
Critics argue the rule reduced market liquidity by making banks less willing to hold inventory, a debate that resurfaces during episodes of bond market stress. For candidates interviewing in sales and trading, understanding the line between market making and prop trading, and how the Volcker Rule polices it, shows command of how modern trading desks actually operate.
