A tight spread refers to the difference between the bid and ask price of a financial instrument, such as a currency pair or stock. A low commission refers to the fee charged by a broker for executing a trade. Both of these factors can have a significant impact on a trader's bottom line, as they can eat into profits. A broker with tight spreads and low commissions can be more attractive to traders, as it allows them to potentially make more money on their trades. However, it's important to note that a broker's spreads and commissions are just one aspect to consider when choosing a broker. Other factors such as regulation, customer service, and trading platforms should also be taken into account.