【中文版】

银行作为金融中介，主要通过吸收存款、发放贷款等方式进行资产负债管理，实现利润最大化。然而，随着金融市场的不断发展和创新，银行为了扩大业务范围、增加利润来源，开始开展表外业务。那么，银行为什么要做表外业务呢？

首先，表外业务可以帮助银行规避风险。在金融市场中，风险是不可避免的，而银行作为资金的中介，需要尽可能地降低自身风险。通过开展表外业务，银行可以将一部分风险转移给其他投资者，从而降低自身风险。

其次，表外业务可以增加银行的利润来源。在传统的资产负债业务中，银行的利润主要来自于存贷款利差。然而，随着市场竞争的加剧和利率市场化的推进，银行的利差空间逐渐缩小。而表外业务作为一种非利息收入，可以为银行带来新的利润增长点，提高银行的盈利能力。

最后，表外业务可以满足客户的多样化需求。随着经济的发展和社会的进步，人们对金融服务的需求越来越多样化。银行通过开展表外业务，可以满足客户的多样化需求，提高客户黏性，从而增加业务机会。

总之，银行开展表外业务是为了扩大业务范围、增加利润来源、规避风险和满足客户需求。这些业务不仅提高了银行的盈利能力，也增强了银行的竞争力和可持续发展能力。

【英文版】

Banks, as financial intermediaries, mainly manage assets and liabilities through absorbing deposits and making loans to achieve profit maximization. However, with the continuous development and innovation of financial markets, banks have begun to carry out off-balance sheet activities in order to expand business scope and increase profit sources. So, why do banks do off-balance sheet business?

Firstly, off-balance sheet business can help banks avoid risks. In financial markets, risk is inevitable, and as a funding intermediary, banks need to minimize their own risks as much as possible. By carrying out off-balance sheet activities, banks can transfer part of the risk to other investors, thus reducing their own risks.

Secondly, off-balance sheet business can increase banks' profit sources. In traditional asset-liability business, banks' profits mainly come from interest rate spreads. However, with the intensification of market competition and the promotion of interest rate liberalization, the interest rate spread of banks is gradually narrowing. Off-balance sheet activities, as a non-interest income, can bring new profit growth points to banks and improve their profitability.

Finally, off-balance sheet business can meet customers' diverse needs. With the development of the economy and society, people's demand for financial services is becoming more and more diverse. Banks can meet diverse needs of customers through off-balance sheet activities to improve customer stickiness and increase business opportunities.

In summary, banks carry out off-balance sheet activities to expand business scope, increase profit sources, avoid risks, and meet customer needs. These activities not only improve banks' profitability, but also enhance their competitiveness and sustainable development capabilities.