Transaction costs
Transaction costs were $38.1 million for the three months ended September 30, 2024, an increase of $7.7 million, or 25%, compared to the prior-year period, partially due to an increase in chargebacks and other operational losses of $2.4 million. Excluding the impact of these non-volume related costs, transaction costs increased by $5.3 million or 18%, while volume increased by 25% compared to the prior year period. Transaction costs grew at a lower rate than volume due to improved commercial terms with our network partners, internal platform optimizations, and the scale benefits of increased transaction volumes.
Transaction costs were $109.0 million for the nine months ended September 30, 2024, an increase of $23.0 million, or 27%, compared to the prior-year period, partially due to an increase in chargebacks and other operational losses of $6.3 million. Excluding the impact of these non-volume related costs, transaction costs increased by $16.7 million or 21%, while volume increased by 23% compared to the prior year period. Transaction costs grew at a lower rate than volume due to improved commercial terms with our banking partners, internal platform optimizations, and the scale benefits of increased transaction volumes.
Other operating expenses
Other operating expenses were $44.9 million for the three months ended September 30, 2024, an increase of $4.6 million, or 11%, compared to the prior-year period, driven by an increase of $4.5 million in information technology expenses and an increase of $1.8 million in ongoing regulatory reserves, partially offset by a decrease of $1.9 million in third-party contractor and consulting expenses.
Other operating expenses were $126.4 million for the nine months ended September 30, 2024, an increase of $5.5 million, or 5%, compared to the prior-year period, driven by an increase of $10.6 million in information technology expenses partially offset by a decrease of $5.0 million in employee compensation, benefits and other employee-related expenses primarily due to a decrease in employee headcount and a decrease of $2.2 million in third-party contractor and consulting expenses.
Research and development expenses
Research and development expenses were $34.6 million for the three months ended September 30, 2024, an increase of $7.7 million, or 28%, compared to the prior-year period, driven by an increase of $5.6 million in employee compensation, benefits and other employee-related expenses in line with an increase in employee headcount and an increase of $0.9 million in information technology expenses.
Research and development expenses were $94.2 million for the nine months ended September 30, 2024, an increase of $10.0 million, or 12%, compared to the prior-year period, driven by an increase of $13.5 million in employee compensation, benefits and other employee-related expenses in line with an increase in employee headcount and an increase of $3.4 million in information technology expenses, partially offset by an increase of $6.9 million in employee compensation costs capitalized as internal use software in connection with ongoing investments in our platform infrastructure.
Sales and marketing expenses
Sales and marketing expenses were $52.3 million for the three months ended September 30, 2024, an increase of $3.6 million, or 7%, compared to the prior-year period, driven by an increase of $4.1 million in expenditures on certain direct marketing efforts, partially offset by a decrease of $1.0 million in marketplace partner commissions.
Sales and marketing expenses were $152.8 million for the nine months ended September 30, 2024, an increase of $7.9 million, or 5%, compared to the prior-year period, driven by an increase of $9.2 million in expenditures on certain direct marketing efforts and an increase of $1.2 million in information technology expenses, partially offset by a decrease of $3.5 million in employee compensation, benefits and other employee-related expenses primarily due to a decrease in employee headcount.
General and administrative expenses
General and administrative expenses were $29.7 million for the three months ended September 30, 2024, an increase of $4.6 million, or 18%, compared to the prior-year period, driven by an increase of $2.9 million in employee compensation, benefits and other employee-related expenses primarily due to an increase in employee headcount and an increase of $1.5 million in M&A related expenses.
General and administrative expenses were $80.0 million for the nine months ended September 30, 2024, an increase of $6.2 million, or 8%, compared to the prior-year period, driven by an increase of $4.5 million in M&A related expenses and an increase of $2.6 million in third-party contractor and consulting expenses.