companies may utilize different estimates that may impact the comparability of our results of operations to those of companies in similar businesses. For a detailed description of our critical accounting estimates, see Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our 2021 Form 10-K. As of March 31, 2022, our critical accounting estimates have not changed from those described in our 2021 Form 10-K.
ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
Interest Rate Risk
We are exposed to the impact of interest rate changes. Our interest rate risk management objectives are to limit the impact of interest rate changes on earnings and cash flows, and optimize overall borrowing costs. To achieve these objectives, we often plan to borrow on a fixed interest rate basis for longer-term debt and utilize interest rate swap agreements on certain variable interest rate debt in order to limit the effects of changes in interest rates on our results of operations. As of March 31, 2022, our debt instruments consisted of borrowings under our line of credit, term loans and mortgage notes.
Fixed Interest Rate Debt. As of March 31, 2022, our fixed interest rate debt consisted of $381.5 million under our mortgage notes and $300.0 million of borrowings under our term loans that were effectively fixed through the use of interest rate swaps. In total, our fixed interest rate debt represented 53.4% of our total consolidated debt as of March 31, 2022. Interest rate fluctuations will generally not affect our future earnings or cash flows on our fixed interest rate debt unless such instruments mature or are otherwise terminated. However, interest rate changes could affect the fair value of our fixed interest rate debt. As of March 31, 2022, the fair value and the carrying value of our consolidated fixed interest rate debt, excluding the values of any associated hedges, was $666.1 million and $681.5 million, respectively. The fair value estimate of this debt was estimated using a discounted cash flow analysis utilizing rates we would expect to pay for debt of a similar type and remaining maturity if the loans were originated on March 31, 2022. Given we generally expect to hold our fixed interest rate debt instruments to maturity or when they otherwise open up for prepayment at par, and the amounts due under such debt instruments should be limited to the outstanding principal balance and any accrued and unpaid interest at such time, we do not expect that the resulting change in fair value of our fixed interest rate debt instruments due to market fluctuations in interest rates, would have a significant impact on our operating cash flows.
Variable Interest Rate Debt. As of March 31, 2022, our consolidated variable interest rate debt consisted of $162.0 million of borrowings under our line of credit, $225.0 million of borrowings under our term loans and $207.6 million under our mortgage notes, which represented 46.6% of our total consolidated debt. Interest rate changes on the variable portion of our consolidated variable-rate debt could impact our future earnings and cash flows, but would not necessarily affect the fair value of such debt. As of March 31, 2022, we were exposed to market risks related to fluctuations in interest rates on $594.6 million of consolidated borrowings. A hypothetical 25 basis points increase in the all-in rate on the outstanding balance of our consolidated variable interest rate debt as of March 31, 2022, would increase our annual interest expense by approximately $1.5 million.
Derivative Instruments. As of March 31, 2022, we had nine outstanding derivative instruments with a total notional amount of $507.6 million. These derivative instruments were comprised of interest rate swaps and interest rate caps that were designed to mitigate the risk of future interest rate increases by either providing a fixed interest rate or capping the variable interest rate for a limited, pre-determined period of time. See “Note 5 to the Condensed Consolidated Financial Statements” for further detail on our derivative instruments. We are exposed to credit risk of the counterparty to our interest rate cap and swap agreements in the event of non-performance under the terms of the agreements. If we were not able to replace these caps or swaps in the event of non-performance by the counterparty, we would be subject to variability of the interest rate on the amount outstanding under our debt that is fixed or capped through the use of the swaps or caps, respectively.
ITEM 4. CONTROLS AND PROCEDURES
Evaluation of Disclosure Controls and Procedures
Under the direction of our principal executive officer and principal financial officer, we evaluated the effectiveness of our disclosure controls and procedures (as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) as of March 31, 2022. Based on this evaluation, our principal executive officer and principal financial officer have concluded that, as of March 31, 2022, our disclosure controls and procedures were effective.
Internal Control Over Financial Reporting
There have not been any changes in our internal control over financial reporting (as such term is defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) during the three months ended March 31, 2022 that have materially affected, or are reasonably