股票平仓是指投资者将持有的股票卖出并清算该交易的过程。在进行股票平仓时，投资者需要支付一定的费用，这常常让人感到困惑。为了解答这个问题，我们需要理解股票平仓费用的来源和作用。

股票平仓所需支付的费用主要包括两部分：手续费和印花税。手续费是投资者进行股票交易时向券商支付的费用，用于覆盖券商提供交易服务所产生的成本，包括交易员工资、交易系统维护费用等。印花税是由政府收取的股票交易税费，根据交易金额的一定比例征收。

手续费的收取是合理的，因为券商作为提供交易服务的中介机构，需要维护并运营强大的交易系统，以便投资者能够方便快捷地完成买卖股票的交易。而这些交易系统的开发、维护和更新都需要付出大量的人力和物力成本。因此，手续费的收取就是为了保障交易市场的正常运转，并为投资者提供高效的交易服务。

印花税的征收是为了调节股票市场，防止过度投机和不稳定的交易行为。印花税的存在可以减少短期高频交易，降低交易风险，同时增加国家财政收入。在一些国家，印花税甚至被用作财政预算的重要组成部分。

需要注意的是，不同国家和地区对于股票平仓费用的征收标准和比例是不同的，投资者在进行股票交易时应该了解并遵守相关规定。

In English:

Why do we need to pay money for stock liquidation?

Stock liquidation refers to the process of selling the stocks held by investors and settling the transaction. When liquidating stocks, investors are required to pay certain fees, which often confuses people. To answer this question, we need to understand the sources and purposes of fees for stock liquidation.

The fees for stock liquidation mainly consist of two parts: commission fees and stamp duty. Commission fees are charges paid by investors to brokers for the trading services they provide, covering costs such as salaries of traders, maintenance fees for trading systems, and more. Stamp duty is a tax imposed by the government on stock transactions, levied at a certain percentage of the transaction amount.

Charging commission fees is reasonable because brokers act as intermediaries providing trading services, and they need to maintain and operate robust trading systems so that investors can complete stock transactions conveniently and efficiently. The development, maintenance, and updates of these trading systems require substantial human and material resources. Therefore, charging commission fees ensures the normal operation of the trading market and offers efficient trading services to investors.

The collection of stamp duty serves to regulate the stock market, preventing excessive speculation and unstable trading activities. The presence of stamp duty can reduce short-term high-frequency trading, lower trading risks, and increase national fiscal revenue. In some countries, stamp duty is even used as a significant component of the fiscal budget.

It is important to note that different countries and regions have different standards and rates for the collection of fees for stock liquidation. Investors should understand and comply with the relevant regulations when engaging in stock trading.