principles may require us to make changes to our systems, processes and control, which could have a significant effect on our reported financial results, cause unexpected financial reporting fluctuations or require us to make costly changes to our operational processes and accounting systems upon or following the adoption of these standards. For additional information regarding the accounting standard updates, see "Accounting Standards Not Yet Adopted" and "Accounting Standards Adopted" sections of Note 1 of Notes to Condensed Consolidated Financial Statements in Item 1 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 September 30, 2018, our retained earnings were $779.9 million. 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.
The failure to obtain favorable terms when we renew our IBX data center leases, or the failure to renew such leases, could harm our business and results of operations.
While we own certain of our IBX data centers, others are leased under long-term arrangements with lease terms expiring at various dates through 2065. These leased centers have all been subject to significant development by us in order to convert them from, in most cases, vacant buildings or warehouses into IBX data centers. Most of our IBX data center leases have renewal options available to us. However, many of these renewal options provide for the rent to be set at then-prevailing market rates. To the extent that then-prevailing market rates or negotiated rates are higher than present rates, these higher costs may adversely impact our business and results of operations, or we may decide against renewing the lease. In the event that an IBX data center lease does not have a renewal option, or we fail to exercise a renewal option in a timely fashion and lose our right to renew the lease, we may not be successful in negotiating a renewal of the lease with the landlord. A failure to renew a lease could force us to exit a building prematurely, which could disrupt our business, harm our customer relationships, expose us to liability under our customer contracts, cause us to take impairment charges and affect our operating results negatively.
We depend on a number of third parties to provide internet connectivity to our IBX data centers; if connectivity is interrupted or terminated, our operating results and cash flow could be materially and adversely affected.
The presence of diverse telecommunications carriers’ fiber networks in our IBX data centers is critical to our ability to retain and attract new customers. We are not a telecommunications carrier, and as such, we rely on third parties to provide our customers with carrier services. We believe that the availability of carrier capacity will directly affect our ability to achieve our projected results. We rely primarily on revenue opportunities from the telecommunications carriers’ customers to encourage them to invest the capital and operating resources required to connect from their centers to our IBX data centers. Carriers will likely evaluate the revenue opportunity of an IBX data center based on the assumption that the environment will be highly competitive. We cannot