Advertising and Marketing Expenses. Advertising and marketing expenses were $111.1 million for the quarter ended September 30, 2021 compared to $52.3 million for the quarter ended September 30, 2020, an increase of $58.8 million, or 112%. The increase was driven by a $44.2 million increase in Member engagement initiatives, digital and media advertising, sponsorship of professional organizations and trade shows; the impact from acquisitions; and a $2.6 million impact driven by the hiring of additional personnel.
On a year-to-date basis, advertising and marketing expenses increased by $171.3 million, or 129%, driven by a $123.1 million increase in Member engagement initiatives, digital and media advertising, sponsorship of professional organizations and trade shows, the impact of acquisitions, and a $6.1 million impact driven by the hiring of additional personnel.
Sales Expenses. Sales expenses were $62.6 million for the quarter ended September 30, 2021 compared to $23.5 million for the quarter ended September 30, 2020, an increase of $39.1 million, or 167%. On a year-to-date basis, sales expense increased $131.1 million, or 218%. The increases for both the quarter and year-to-date periods substantially reflect the impact from acquisitions.
Technology and Development Expenses. Technology and development expenses were $80.3 million for the quarter ended September 30, 2021 compared to $30.0 million for the quarter ended September 30, 2020, an increase of $50.3 million, or 168%. On a year-to-date basis, technology and development expenses increased by $166.8 million, or 231%. In addition to substantially reflecting the impact of acquisitions, the increases for the quarter and year-to-date periods were driven by increases of $3.0 million and $12.0 million, respectively, due to the hiring of additional personnel and increases of $0.9 million and $10.3 million, respectively, due to ongoing projects to continuously improve our technology portfolio and other similar items.
Acquisition, Integration and Transformation Costs. Acquisition, integration and transformation costs include investment banking, financing, legal, accounting, consultancy, integration, fair value changes related to contingent consideration and certain other transaction costs related to mergers and acquisitions. It also includes costs related to certain internal business transformation initiatives focused on integrating and optimizing various operations and systems, including upgrading our customer relationship management (CRM) and enterprise resource planning (ERP) systems.
Acquisition, integration and transformation costs were $4.3 million for the quarter ended September 30, 2021 compared to $25.4 million for the quarter ended September 30, 2020, a decrease of $21.1 million, primarily driven by expenses incurred for the Livongo merger in the prior year. These costs also decreased by $8.6 million on a year-to-date basis due to the timing of expenditures to drive integration and transformation activities resulting from the InTouch, Livongo and Consultant Connect acquisitions.
General and Administrative Expenses. General and administrative expenses were $103.0 million for the quarter ended September 30, 2021 compared to $59.7 million for the quarter ended September 30, 2020, an increase of $43.3 million, or 72%. The increase primarily reflects the impact of acquisitions. Other expenses, including office-related charges, bank charges, therapist recruiting, liability insurance, legal fees and related contingencies and bad debt expenses, increased a combined total of $16.6 million, reflecting the overall impact of growth on the business.
On a year-to-date basis, general and administrative expenses increased by $156.7 million, or 96%. The increase primarily reflects the impact of acquisitions and a $12.6 million increase in employee-related expenses reflecting the acceleration of the adoption of virtual care stemming from the COVID-19 pandemic. Other expenses, including office-related charges, bank charges, therapist recruiting, liability insurance, legal fees and related contingencies and bad debt expenses, increased a combined total of $50.0 million, reflecting the overall impact of growth on the business.
Depreciation and Amortization. Depreciation and amortization was $51.9 million for the quarter ended September 30, 2021 compared to $12.9 million for the quarter ended September 30, 2020, an increase of $39.0 million. Depreciation and amortization was $151.9 million for the nine months ended September 30, 2021 compared to $32.5 million, an increase of $119.4 million on a year-to-date basis. This increase was due to additional amortization and depreciation expense substantially related to intangible assets and fixed assets acquired from recent acquisitions.
Loss on Extinguishment of Debt. Loss on extinguishment of debt was $0.8 million for the quarter ended September 30, 2021 compared to $1.2 million for the quarter ended September 30, 2020, a decrease of $0.4 million. On a year-to-date basis, loss on extinguishment of debt increased by $34.8 million. This increase was primarily due to the exchanges and conversions of the 2025 Notes.