•Protect our team. We instituted a work-from-home policy for substantially all employees in early March. This allowed responsible social distancing to keep our team safe. We are also providing technology support, training and other resources to support our team members during this unique time.
Technology and development expenses primarily consist of personnel costs and related expenses for our technology staff, which includes information technology development and infrastructure support, including third-party services. It also includes expenses associated with development of new products and offerings.
Depreciation and amortization expenses consist of depreciation of property, equipment, and internally-developed software, as well as amortization of finite-lived intangible assets.
Net cash used in investing activities was $76.7 million for the year ended December 31, 2020. The year over year increase of $48.7 million was primarily due to the Aquarium acquisition. As of December 31, 2020, we had $95.4 million in short-term and long-term investments in our insurance entities, APIC and WICL Segregated Account AX. These investments are held to satisfy statutory requirements and we anticipate that we will need to maintain greater amounts of risk-based capital if our pet enrollments continue to grow.
We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2020, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 11, 2021 expressed an unqualified opinion thereon.
The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") and include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
The Company does not expect any credit losses from its held-to-maturity investments, considering the composition of the investment portfolio and the credit loss history of these investments. For available-for-sale debt securities, the Company determined that the unrealized losses were immaterial and due to non-credit factors. The Company does not intend to sell, nor is it more likely than not that the Company will be required to sell, the securities prior to maturity or prior to the recovery of the amortized cost basis.
The chief operating decision maker reviews revenue and operating income (loss) to evaluate segment performance. Revenue, veterinary invoice expense, other cost of revenue, and sales and marketing expenses are generally directly attributed to each segment. Other operating expenses, such as technology and development expense, general and administrative expense, and depreciation and amortization are allocated proportionately based on revenue in each segment. Interest and other expenses and income taxes are not allocated to the segments, nor included in the measure of segment profit or loss. The Company does not analyze discrete segment balance sheet information related to long-term assets.