Distribution segment net sales for the three months ended March 31, 2024 increased 11%, or $8.3 million, to $86.8 million compared to $78.6 million for the same period in the prior year. Adjusted gross billings for the Distribution segment for the three months ended March 31, 2024 increased 16%, or $46.9 million, to $334.6 million compared to $287.7 million for the same period in the prior year. Net sales increased at a rate greater than adjusted gross billings due to the impact of hardware and software sales recognized during the current period in our Distribution segment, which are recorded on a gross basis.
Solutions segment net sales for the three months ended March 31, 2024, decreased 14%, or $0.9 million, to $5.6 million compared to $6.5 million for the same period in the prior year. Adjusted gross billings for the Solutions segment for the three months ended March 31, 2024 increased 9%, or $1.6 million, to $20.6 million compared to $19.0 million for the same period in the prior year. Net sales decreased while adjusted gross billings increased due to the aforementioned differences in the product mix between the two periods.
During the three months ended March 31, 2024, the Company had two major customers that accounted for 20% and 15%, respectively, of our total net sales. During the three months ended March 31, 2023, the Company had two major customers that accounted for 19% and 14%, respectively, of our total net sales. The Company had two major vendors that accounted for 16% and 10%, respectively, of total purchases during the three months ended March 31, 2024 and 21% and 10%, respectively, of total purchases during the three months ended March 31, 2023.
Gross Profit
Gross profit for the three months ended March 31, 2024 increased 12%, or $1.8 million, to $17.0 million compared to $15.2 million for the same period in the prior year.
Distribution segment gross profit for the three months ended March 31, 2024 increased 12%, or $1.5 million, to $14.2 million compared to $12.7 million for the same period in the prior year. The increase in Distribution segment gross profit was due to organic growth from our existing vendor partnerships, partially offset by higher early pay discounts and other rebates and discounts offered to our customers as a percentage of adjusted gross billings.
Solutions segment gross profit for the three months ended March 31, 2024 increased 13%, or $0.3 million, to $2.8 million compared to $2.5 million for the same period in the prior year. This increase was driven by the aforementioned increase in adjusted gross billings compared to the same period in the prior year.
Customer rebates and discounts for the three months ended March 31, 2024 were $3.3 million compared to $3.9 million for the same period in the prior year. Customer rebates and discounts vary based on terms of rebate and early pay discount programs offered to customers and timing of payments ultimately received from our customers.
Vendor rebates and discounts for the three months ended March 31, 2024 were $1.9 million compared to $1.7 million for the same period in the prior year. Vendor rebates are dependent on programs offered by our vendors and in some cases reaching certain volume targets set by our vendors or meeting certain early payment programs offered by our vendors. The Company monitors vendor rebate levels, competitive pricing, and gross profit margins carefully.
Selling, General and Administrative Expenses
SG&A expenses for the three months ended March 31, 2024 increased 22%, or $2.3 million, to $12.5 million compared to $10.2 million for the same period in the prior year. SG&A expenses were 3.5% of adjusted gross billings for the three months ended March 31, 2024, compared to 3.4% for the same period in the prior year.
The remaining increase in SG&A expenses were primarily due to increased salaries, commission and personnel costs in support of our continued investment in our infrastructure to drive future growth, including new personnel, employee training and development. The Company expects that its SG&A expenses, as a percentage of adjusted gross billings, may vary depending on changes in sales volume, as well as the levels of continuing investments to drive future growth.
Depreciation and Amortization Expense
Depreciation and amortization expense for the three months ended March 31, 2024, increased 22%, or $0.2 million, to $0.9 million compared to $0.7 million for the same period in the prior year.