Revenues from the Synodex segment were $2.9 million and $3.7 million for the nine months ended September 30, 2021 and 2020, respectively, a decrease of $0.8 million or 22%. The decrease was primarily attributable to lower volumes from three existing clients.
Revenues from the Agility segment were $9.6 million and $8.5 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $1.1 million or 13%. The increase was attributable to higher volumes from subscriptions to our Agility AI-enabled industry platform and newswire product.
One client in the DDS segment generated approximately 11% and 14% of the Company’s total revenues for the nine months ended September 30, 2021 and 2020, respectively. No other client accounted for 10% or more of total revenues during these periods. Further, revenues from non-U.S. clients accounted for 47% and 54% of the Company’s total revenues for the nine months ended September 30, 2021 and 2020, respectively.
Direct Operating Costs
Direct operating costs consist of direct and indirect labor costs, occupancy costs, data center hosting fees, content acquisition costs, depreciation and amortization, travel, telecommunications, computer services and supplies, realized gain (loss) on forward contracts, foreign currency revaluation gain (loss), and other direct expenses that are incurred in providing services to our clients.
Direct operating costs were $31.2 million and $29.2 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $2.0 million. This increase was primarily due to direct and indirect labor costs of $3.2 million, offset in part by a $0.8 million foreign exchange gain and a $0.4 million decrease in other direct operating expenditures. Direct operating costs as a percentage of total revenues were 62% and 68% for the nine months ended September 30, 2021 and 2020, respectively. The decrease in direct operating costs as a percentage of total revenues was primarily attributable to increased revenues in the DDS and Agility segments, offset in part by decreased revenues in the Synodex segment and increased direct operating costs in all segments.
Direct operating costs for the DDS segment were approximately $23.1 million and $21.7 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $1.4 million. This increase was primarily due to an increase in direct and indirect labor costs of $2.8 million, offset by a $0.8 million foreign exchange gain and a $0.6 million reduction in other direct operating expenditures. Direct operating costs for the DDS segment as a percentage of DDS segment revenues were 61% and 71% for the nine months ended September 30, 2021 and 2020, respectively. The decrease in direct operating costs as a percentage of segment revenues was primarily attributable to higher revenues, offset in part by an increase in direct operating costs.
Direct operating costs for the Synodex segment were $2.7 million and $2.6 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $0.1 million. The increase was primarily due to an increase in technology and direct labor costs in anticipation of increased revenues in the coming quarters. Direct operating costs for the Synodex segment as a percentage of Synodex segment revenues were 93% and 70% for the nine months ended September 30, 2021 and 2020, respectively. The increase in direct operating costs as a percentage of segment revenues during the quarter was primarily due to lower revenues and an increase in direct operating costs.
Direct operating costs for the Agility segment were $5.4 million and $4.9 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $0.5 million. The increase was due to higher software amortization costs and new hires during the current period. Direct operating costs for the Agility segment as a percentage of Agility segment revenues were 56% and 58% for the nine months ended September 30, 2021 and 2020, respectively. The decrease in direct operating costs as a percentage of segment revenues during the quarter was primarily due to higher revenue from subscriptions to our Agility AI-enabled platform and newswire products, offset in part by an increase in direct operating costs.
Selling and Administrative Expenses
Selling and administrative expenses consist of management and administrative salaries, sales and marketing costs including commissions, new services research and related software development, third-party software, advertising and trade conferences, professional fees and consultant costs, and other administrative overhead costs.
Selling and administrative expenses were $19.8 million and $13.8 million for the nine months ended September 30, 2021 and 2020, respectively, an increase of $6.0 million. This increase was primarily due to higher payroll and payroll related costs of $4.9 million for new hires, commissions, stock-based compensation, incentives, and bonuses, and higher marketing related costs of $1.1 million. Selling and administrative expenses as a percentage of total revenues were 39% and 32% for the nine months ended September 30, 2021 and 2020, respectively. The increase in selling and administrative expenses as a percentage of total revenues was primarily attributable