What is the transaction cost paid by the client when an ETF is purchased?

When a client purchases an Exchange-Traded Fund (ETF), the primary transaction cost incurred is a commission. This commission is typically charged by the brokerage firm executing the trade. It is important to note that this cost is applicable each time a transaction is made, mirroring the costs associated with buying or selling stocks.

The other options, such as a service fee, management fee, and processing fee, are generally associated with different aspects of investment or fund management, but they do not directly occur at the moment of purchasing an ETF. A service fee could relate to ongoing account maintenance or advisory services, a management fee pertains to the ongoing expense of managing the fund's investment portfolio, and a processing fee may refer to costs associated with the administrative handling of transactions but is not the primary charge when buying an ETF. Therefore, the commission stands out as the most relevant and immediate transaction cost for clients purchasing an ETF.