What practice is limited by the Volcker rule of the Dodd-Frank Act?

The Volcker Rule, which is part of the Dodd-Frank Wall Street Reform and Consumer Protection Act, primarily restricts banking entities from engaging in proprietary trading, specifically targeting investments in hedge funds and private equity funds. This regulation was developed to prevent banks from making high-risk investments that could jeopardize customer deposits and financial stability.

Proprietary trading refers to financial institutions investing their own funds for their own profit, rather than on behalf of customers. By limiting banks' ability to invest in hedge funds, the Volcker Rule aims to reduce systemic risk within the financial system and protect the broader economy from excessive risk-taking behavior by banks that could result in significant losses.

In the context of the other choices, while high-frequency trading, trading in commodities, and excessive risk-taking in derivatives can be risky practices, they are not specifically limited by the Volcker Rule. The focus of the rule is primarily on proprietary trading as it pertains to hedge funds and private equity, thereby making the connection clearer for the specific practice being restricted.