# Trading Books Explained: Impacts, Risks, and Strategies for Banks

## What Is a Trading Book?

A trading book is the portfolio of [financial instruments](https://www.investopedia.com/terms/f/financialinstrument.asp) held by a brokerage or bank. They might be bought or sold to facilitate trading for customers or to hedge against different forms of risk.

Trading books can range from hundreds of thousands to billions of dollars, depending on the institution. Due to their size, institutions require robust risk management to prevent significant losses from spreading throughout the financial system.

A key difference between a trading book and a banking book is that trading books hold securities for short-term trading, while banking books hold securities for long-term maturity. There are numerous instances of trading book losses having a significant effect on the global financial ecosystem, such as the LTCM collapse and the 1998 Russian crisis.

### Key Takeaways

*   A trading book tracks tradeable assets held by financial institutions, with portfolios potentially worth billions.
*   Unlike banking books, trading books are for assets intended for short-term trading rather than long-term holding.
*   Losses in trading books can have widespread global financial impacts, as seen in past crises like 2008.
*   Advanced risk metrics are crucial for managing trading book risks, especially in high-leverage scenarios.
*   Trading books can serve as legal documents and planning tools for future financial trades.

## Functionality of Trading Books in Financial Institutions

Most institutions use advanced risk [metrics](https://www.investopedia.com/terms/m/metrics.asp) to manage and reduce risks in their trading books. These books act as accounting ledgers, tracking securities that are bought and sold regularly and recording past trading activities. Unlike banking books, trading books hold securities for short-term trading, not for long-term maturity.

> **Fast Fact**
>
> Securities held in a trading book must be eligible for active trading.

As security prices change, trading books record gains and losses that impact the institution's financial health.  

## Impact of Trading Book Losses: Lessons from History

Trading books can lead to large losses for financial institutions, often due to high leverage. They can also lose significantly from large bets on specific securities or sectors by [rogue traders](https://www.investopedia.com/terms/r/roguetrader.asp).

Trading book losses can have a widespread, global impact when affecting many institutions simultaneously, as seen in events like the LTCM collapse, the 1998 Russian crisis, and the 2008 [Lehman Brothers](https://www.investopedia.com/terms/l/lehman-brothers.asp) bankruptcy. The global [credit crunch](https://www.investopedia.com/terms/c/creditcrunch.asp) and [financial crisis](https://www.investopedia.com/terms/f/financial-crisis.asp) of 2008 were significantly attributable to the hundreds of billions of losses sustained by global [investment banks](https://www.investopedia.com/terms/i/investmentbank.asp) in the mortgage-backed securities portfolios held within their trading books. During that crisis, [Value at Risk](https://www.investopedia.com/terms/v/var.asp) (VaR) models were used to quantify trading risks in trading books. Banks transferred their risk from the banking book to trading books because VaR values were low.

Attempts to disguise mortgage-backed security trading book losses during the financial crisis ultimately resulted in criminal charges being brought against a former vice president of Credit Suisse Group. In 2014, Citigroup Inc. purchased the commodity trading books held by Credit Suisse. Credit Suisse participated in the sale in response to regulatory pressure and its intent to lower its involvement in commodities investing.

## What Is Included in the Trading Book?

All of a financial institution's tradeable assets are listed in the trading book.

## What Is the Difference Between a Bank Book and a Trading Book?

The trading book lists assets intended for short-term trading, while the bank book lists all other assets intended for earning interest.

## What Are the Benefits of a Trading Book?

A trading book is a legal document used as evidence in court and for planning future trades.  

## The Bottom Line

A trading book is a ledger that tracks a financial institution's tradeable assets, emphasizing its role in short-term trading and risk hedging. There is great potential for market fluctuations to affect the value of the trading book's assets, not to mention the subsequent wide-ranging impact these fluctuations can have on the financial market. This underscores the importance of risk management.  
  
The significant difference between trading books and banking books is that trading books focus on short-term trades, while banking books maintain a focus on long-term holding until maturity. A prime example of the historical impact is the 2008 financial crisis, which demonstrates the global repercussions of insufficiently managed trading books. Sophisticated risk management strategies within institutions are necessary to manage potentially large scale of trading books, which often reaching billions in investments. There is great legal importance to maintaining a trading book as it serves as an official record and can be used as evidence in legal or regulatory actions and future trade planning.  

> **Article Sources**
>
> 1.  United States Department of Justice. "[Former Credit Suisse Vice President Sentenced In Manhattan Federal Court In Connection With Scheme To Hide Losses In Mortgage-Backed Securities Trading Book](https://www.justice.gov/usao-sdny/pr/former-credit-suisse-vice-president-sentenced-manhattan-federal-court-connection-scheme)."
>     
> 2.  Reuters. "[Citi Buys Credit Suisse Commodities Trading Book](https://www.reuters.com/article/us-citi-commodities-credt-suisse-grp/citi-buys-credit-suisse-commodities-trading-book-idUSKBN0JX1MW20141219)."