growth rate is not necessarily indicative of future operating results. Prior to 2008, we had generated net losses every fiscal year since inception. It is possible that we may not be able to generate net income on a quarterly or annual basis in the future. In addition, a relatively large portion of our expenses are fixed in the short-term, particularly with respect to lease and personnel expenses, depreciation and amortization and interest expenses. Therefore, our results of operations are particularly sensitive to fluctuations in revenues. As such, comparisons to prior reporting periods should not be relied upon as indications of our future performance. In addition, our operating results in one or more future quarters may fail to meet the expectations of securities analysts or investors.
Our days sales outstanding ("DSO") may be negatively impacted by process and system upgrades and acquisitions.
Our DSO may be negatively impacted by ongoing process and system upgrades which can impact our customers' experience in the short term, together with integrating recent acquisitions into our processes and systems, which may have a negative impact on our operating cash flows, liquidity and financial performance.
Our reported financial results may be adversely affected by changes in U.S. GAAP.
We prepare our consolidated financial statements in conformity with U.S. GAAP. A change in these principles can have a significant effect on our reported financial position and financial results. In addition, the adoption of new or revised accounting principles may require us to make changes to our systems, processes and controls, which could require us to make costly changes to our operational processes and accounting systems upon or following the adoption of these standards. For example, we adopted the new lease accounting standard on January 1, 2019, which requires lessees to recognize right-of-use assets and right-of-use liabilities related to operating leases. As a result, we will record significant operating lease obligations on our balance sheet and make other changes in our financial statements, which will have a material effect on our financial statements. We are also implementing a new lease accounting tool, which may impact our accounting and reporting process. This, and other future changes to accounting rules, could have a material adverse effect on the reporting of our business, financial condition and results of operations. For additional information regarding the accounting standard updates, see the "Accounting Standards Not Yet Adopted" and "Accounting Standards Adopted" sections of Note 1 of Notes to Condensed Consolidated Financial Statements in Item I of this Quarterly Report on Form 10-Q.
We may incur goodwill and other intangible asset impairment charges, or impairment charges to our property, plant and equipment, which could result in a significant reduction to our earnings.
In accordance with U.S. GAAP, we are required to assess our goodwill and other intangible assets annually, or more frequently whenever events or changes in circumstances indicate potential impairment, such as changing market conditions or any changes in key assumptions. If the testing performed indicates that an asset may not be recoverable, we are required to record a non-cash impairment charge for the difference between the carrying value of the goodwill or other intangible assets and the implied fair value of the goodwill or other intangible assets in the period the determination is made.
We also periodically monitor the remaining net book values of our property, plant and equipment, including at the individual IBX data center level. Although each individual IBX data center is currently performing in accordance with our expectations, the possibility that one or more IBX data centers could begin to under-perform relative to our expectations is possible and may also result in non-cash impairment charges.
These charges could be significant, which could have a material adverse effect on our business, results of operations or financial condition.
We have incurred substantial losses in the past and may incur additional losses in the future.
As of March 31, 2019, our retained earnings were $1.0 billion. Although we have generated net income for each fiscal year since 2008, except for the year ended December 31, 2014, we are currently investing heavily in our future growth through the build out of multiple additional IBX data centers, expansions of IBX data centers and acquisitions of complementary businesses. As a result, we will incur higher depreciation and other operating expenses, as well as acquisition costs and interest expense, that may negatively impact our ability to sustain profitability in future periods unless and until these new IBX data centers generate enough revenue to exceed their operating costs and cover the additional overhead needed to scale our business for this anticipated growth. The current global financial uncertainty may also impact our ability to sustain profitability if we cannot generate sufficient revenue to offset the increased costs of our recently-opened IBX data centers or IBX data centers currently under construction. In addition, costs associated with the acquisition and integration of any acquired companies, as well as the additional interest expense associated with debt financing we have undertaken to fund our growth initiatives, may also negatively impact our ability to sustain profitability. Finally, given the competitive and evolving nature of the industry in which we operate, we may not be able to sustain or increase profitability on a quarterly or annual basis.