in light of the above actions , resources , expectations and conditions , we believe that we are well positioned to weather the present disruptions facing the real estate industry and , in particular , the real estate healthcare industry , including senior living . however , as a result of the covid-19 pandemic , some of our tenants have requested relief from their obligations to pay rent due to us . while the number and value of these monthly requests have been declining , we continue to evaluate these requests as they are made on a tenant-by-tenant basis . as of february 23 , 2021 , we had granted requests to 72 of our tenants to defer rent payments totaling $ 2.1 million with respect to leases that represented , as of december 31 , 2020 , approximately 5.5 % of our annualized rental income . those 72 of our tenants consist of 71 tenants in our office portfolio segment , which accounted for $ 1.8 million of deferrals , which represented approximately 4.8 % of our office portfolio segment annualized rental income as of december 31 , 2020 , and one triple net senior living tenant . as of december 31 , 2020 , we recognized an increase in our accounts receivable balance related to these deferred rent payments of $ 1.5 million . these tenants were obligated to pay , in most cases , the deferred rents in 12 equal monthly installments beginning in september 2020. for the three months ended december 31 , 2020 , we collected approximately 99 % of our contractual rents due from tenants in our office portfolio segment . 65 while these deferred amounts have not negatively impacted our results of operations , the deferred rents have temporarily reduced our operating cash flows . the covid-19 pandemic and related public health restrictions have had a negative impact on us and our business . for a discussion of and the risks relating to the covid-19 pandemic on us and our business , see elsewhere in this annual report on form 10-k , including `` warning concerning forward-looking statements , `` part i , item 1 `` business `` and part i , item 1a `` risk factors `` . portfolio overview the following tables present an overview of our portfolio ( dollars in thousands , except investment per square foot or unit data ) : replace_table_token_1_th replace_table_token_2_th ( 1 ) represents gross book value of real estate assets at cost plus certain acquisition costs , before depreciation and purchase price allocations and less impairment write downs , if any . amounts include $ 114,778 of gross book value of 15 properties classified as held for sale as of december 31 , 2020 , which amounts are included in assets of properties held for sale in our consolidated balance sheet . ( 2 ) represents gross book value of real estate assets divided by number of rentable square feet or living units , as applicable , at december 31 , 2020 . ( 3 ) includes $ 47,387 of revenues and $ ( 2,996 ) of noi from properties that we sold during the year ended december 31 , 2020 and $ 41,496 of revenues and $ 7,725 of noi from properties classified as held for sale in our consolidated balance sheet as of december 31 , 2020 . ( 4 ) we calculate our noi on a consolidated basis and by reportable segment . our definition of noi and our reconciliation of net income ( loss ) to noi are included below under the heading “ non-gaap financial measures ” . ( 5 ) our medical office and life science property leases include some triple net leases where , in addition to paying fixed rents , the tenants assume the obligation to operate and maintain the properties at their expense , and some net and modified gross leases where we are responsible for the operation and maintenance of the properties and we charge tenants for some or all of the property operating costs . a small percentage of our medical office and life science property leases are full-service leases where we receive fixed rent from our tenants and no reimbursement for our property operating costs . ( 6 ) includes $ 11,364 of revenues and $ ( 5,786 ) of noi from seven senior living communities that were closed during the year ended december 31 , 2020 . 66 ( 7 ) residents fees and services for the year ended december 31 , 2020 for our shop segment is net of a $ 3,842 reserve for a medicare refund we paid in january 2021. property operating expenses for the year ended december 31 , 2020 for our shop segment includes $ 1,928 of estimated penalties , compliance costs and professional fees , net of management fees reimbursable by five star , related to the medicare refund . for further information regarding this matter , see elsewhere in this annual report on form 10-k , including note 6 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k. ( 8 ) medical office and life science property occupancy data is as of december 31 , 2020 and 2019 and includes ( i ) out of service assets undergoing redevelopment , ( ii ) space which is leased but is not occupied or is being offered for sublease by tenants and ( iii ) space being fitted out for occupancy . ( 9 ) excludes data for periods prior to our ownership of certain properties , data for properties sold or classified as held for sale and data for which there was a transfer of operations during the periods presented . story_separator_special_tag 72 replace_table_token_7_th nm – not meaningful office portfolio : replace_table_token_8_th ( 1 ) consists of medical office and life science properties that we have owned and which have been in service continuously since january 1 , 2019 , including our life science property owned in a joint venture arrangement in which we own a 55 % equity interest ; excludes properties classified as held for sale or out of service undergoing redevelopment , if any . ( 2 ) prior periods exclude space remeasurements made subsequent to those periods . ( 3 ) medical office and life science property occupancy includes ( i ) out of service assets undergoing redevelopment , ( ii ) space which is leased but is not occupied or is being offered for sublease by tenants , and ( iii ) space being fitted out for occupancy . comparable property occupancy excludes out of service assets undergoing redevelopment . replace_table_token_9_th ( 1 ) consists of medical office and life science properties that we have owned and which have been in service continuously since january 1 , 2019 , including our life science property owned in a joint venture arrangement in which we own a 55 % equity interest ; excludes properties classified as held for sale or out of service undergoing redevelopment , if any . 73 rental income . rental income decreased primarily due to our disposition of 32 properties since january 1 , 2019 , assets being taken out of service and or undergoing redevelopment and a decrease in rental income at our comparable properties . rental income decreased at our comparable properties primarily due to reduced parking revenue at certain of our comparable properties related to the covid-19 pandemic and increased bad debt , partially offset by higher real estate tax and other property operating expense reimbursements at certain of our comparable properties . property operating expenses . property operating expenses consist of real estate taxes , utility expenses , insurance , management fees , salaries and benefit costs of property level personnel , repairs and maintenance expense , cleaning expense and other direct costs of operating these properties . the decrease in property operating expenses is primarily due to our disposition of 32 properties since january 1 , 2019 , partially offset by an increase in property operating expenses at our comparable properties . property operating expenses at our comparable properties increased primarily due to increases in real estate taxes and insurance expense , partially offset by decreases in utility expenses , landscaping expenses , parking expenses and other direct costs at certain of our comparable properties . net operating income . the change in noi reflects the net changes in rental income and property operating expenses described above . shop : replace_table_token_10_th ( 1 ) consists of senior living communities that we have owned and which have been operated by the same operator continuously since january 1 , 2019 ; excludes communities classified as held for sale or closed , if any . ( 2 ) average monthly rate is calculated by taking the average daily rate , which is defined as total residents fees and services divided by occupied units during the period , and multiplying it by 30 days . replace_table_token_11_th ( 1 ) consists of senior living communities that we have owned and which have been operated by the same operator continuously since january 1 , 2019 ; excludes communities classified as held for sale or closed , if any . as a result of routine monitoring protocols that are a part of five star 's compliance program activities related to medicare billing , five star discovered potentially inadequate documentation at one of our senior living communities that five star manages . this monitoring was not initiated in response to any specific complaint or allegation but rather was of the type that five star periodically undertakes to test its compliance with applicable medicare billing rules . we and five star voluntarily disclosed this matter to the oig pursuant to the oig 's provider self-disclosure protocol . in january 2021 , we and five star settled this matter with the oig and we agreed to pay approximately $ 5,763 in exchange for a customary release , but we and five star did not admit any liability . we paid that amount to the oig in january 2021. five star refunded to us $ 115 of management fees it previously received relating to the medicare payments we refunded to the oig . with respect to this settlement amount , we accrued a revenue reserve of $ 3,842 at december 31 , 2020 for historical medicare payments we received and agreed to repay to the oig and we recorded expenses of $ 1,921 for the year ended december 31 , 2020 for oig-imposed penalties . rental income . rental income decreased due to the termination of our previously existing master leases with five star . pursuant to the restructuring transaction , effective january 1 , 2020 , our previously existing master leases and management and 74 pooling agreements with five star were terminated and replaced with the five star management agreements for all of our senior living communities operated by five star . see note 6 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k for information regarding the restructuring transaction . residents fees and services . residents fees and services are the revenues earned at our managed senior living communities . we recognize these revenues as services are provided and related fees are accrued . residents fees and services increased primarily due to the restructuring transaction and the resulting change to our management arrangement with five star for all of our senior living communities that it operates and our acquisition of one active adult rental property since january 1 , 2019 , partially offset by decreases in occupancy and average monthly rate primarily due to the impact of the covid-19

debt covenants our principal debt obligations at december 31 , 2020 were : ( 1 ) $ 2.7 billion outstanding principal amount of senior unsecured notes ; ( 2 ) $ 200.0 million outstanding principal amount under our term loan ( which we prepaid in february 2021 ) ; and ( 3 ) $ 684.5 million aggregate principal amount of mortgage notes ( excluding premiums , discounts and net debt issuance costs ) secured by seven properties . on february 8 , 2021 , we issued $ 500.0 million aggregate principal amount of our 4.375 % senior notes due 2031. we used net proceeds from this offering to prepay our $ 200.0 million term loan and expect to use the remaining net proceeds to redeem all of our outstanding 6.75 % senior notes due 2021 in june 2021 , when those notes become redeemable with no prepayment premium . for further information regarding our indebtedness , see note 9 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k. our senior unsecured notes are governed by our senior unsecured notes indentures and their supplements . our credit agreement and our senior unsecured notes indentures and their supplements provide for acceleration of payment of all amounts outstanding upon the occurrence and continuation of certain events of default , such as , in the case of our credit agreement , a change of control of us , as defined , which includes rmr llc ceasing to act as our business and property manager . our senior unsecured notes indentures and their supplements and our credit agreement also contain covenants that restrict our ability to 84 incur debts , including debts secured by mortgages on our properties , in excess of calculated amounts and require us to maintain various financial ratios , and our credit agreement contains covenants that restrict our ability to make distributions to our shareholders in certain circumstances .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```debt covenants our principal debt obligations at december 31 , 2020 were : ( 1 ) $ 2.7 billion outstanding principal amount of senior unsecured notes ; ( 2 ) $ 200.0 million outstanding principal amount under our term loan ( which we prepaid in february 2021 ) ; and ( 3 ) $ 684.5 million aggregate principal amount of mortgage notes ( excluding premiums , discounts and net debt issuance costs ) secured by seven properties . on february 8 , 2021 , we issued $ 500.0 million aggregate principal amount of our 4.375 % senior notes due 2031. we used net proceeds from this offering to prepay our $ 200.0 million term loan and expect to use the remaining net proceeds to redeem all of our outstanding 6.75 % senior notes due 2021 in june 2021 , when those notes become redeemable with no prepayment premium . for further information regarding our indebtedness , see note 9 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k. our senior unsecured notes are governed by our senior unsecured notes indentures and their supplements . our credit agreement and our senior unsecured notes indentures and their supplements provide for acceleration of payment of all amounts outstanding upon the occurrence and continuation of certain events of default , such as , in the case of our credit agreement , a change of control of us , as defined , which includes rmr llc ceasing to act as our business and property manager . our senior unsecured notes indentures and their supplements and our credit agreement also contain covenants that restrict our ability to 84 incur debts , including debts secured by mortgages on our properties , in excess of calculated amounts and require us to maintain various financial ratios , and our credit agreement contains covenants that restrict our ability to make distributions to our shareholders in certain circumstances .
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 Suspicious Activity Report : in light of the above actions , resources , expectations and conditions , we believe that we are well positioned to weather the present disruptions facing the real estate industry and , in particular , the real estate healthcare industry , including senior living . however , as a result of the covid-19 pandemic , some of our tenants have requested relief from their obligations to pay rent due to us . while the number and value of these monthly requests have been declining , we continue to evaluate these requests as they are made on a tenant-by-tenant basis . as of february 23 , 2021 , we had granted requests to 72 of our tenants to defer rent payments totaling $ 2.1 million with respect to leases that represented , as of december 31 , 2020 , approximately 5.5 % of our annualized rental income . those 72 of our tenants consist of 71 tenants in our office portfolio segment , which accounted for $ 1.8 million of deferrals , which represented approximately 4.8 % of our office portfolio segment annualized rental income as of december 31 , 2020 , and one triple net senior living tenant . as of december 31 , 2020 , we recognized an increase in our accounts receivable balance related to these deferred rent payments of $ 1.5 million . these tenants were obligated to pay , in most cases , the deferred rents in 12 equal monthly installments beginning in september 2020. for the three months ended december 31 , 2020 , we collected approximately 99 % of our contractual rents due from tenants in our office portfolio segment . 65 while these deferred amounts have not negatively impacted our results of operations , the deferred rents have temporarily reduced our operating cash flows . the covid-19 pandemic and related public health restrictions have had a negative impact on us and our business . for a discussion of and the risks relating to the covid-19 pandemic on us and our business , see elsewhere in this annual report on form 10-k , including `` warning concerning forward-looking statements , `` part i , item 1 `` business `` and part i , item 1a `` risk factors `` . portfolio overview the following tables present an overview of our portfolio ( dollars in thousands , except investment per square foot or unit data ) : replace_table_token_1_th replace_table_token_2_th ( 1 ) represents gross book value of real estate assets at cost plus certain acquisition costs , before depreciation and purchase price allocations and less impairment write downs , if any . amounts include $ 114,778 of gross book value of 15 properties classified as held for sale as of december 31 , 2020 , which amounts are included in assets of properties held for sale in our consolidated balance sheet . ( 2 ) represents gross book value of real estate assets divided by number of rentable square feet or living units , as applicable , at december 31 , 2020 . ( 3 ) includes $ 47,387 of revenues and $ ( 2,996 ) of noi from properties that we sold during the year ended december 31 , 2020 and $ 41,496 of revenues and $ 7,725 of noi from properties classified as held for sale in our consolidated balance sheet as of december 31 , 2020 . ( 4 ) we calculate our noi on a consolidated basis and by reportable segment . our definition of noi and our reconciliation of net income ( loss ) to noi are included below under the heading “ non-gaap financial measures ” . ( 5 ) our medical office and life science property leases include some triple net leases where , in addition to paying fixed rents , the tenants assume the obligation to operate and maintain the properties at their expense , and some net and modified gross leases where we are responsible for the operation and maintenance of the properties and we charge tenants for some or all of the property operating costs . a small percentage of our medical office and life science property leases are full-service leases where we receive fixed rent from our tenants and no reimbursement for our property operating costs . ( 6 ) includes $ 11,364 of revenues and $ ( 5,786 ) of noi from seven senior living communities that were closed during the year ended december 31 , 2020 . 66 ( 7 ) residents fees and services for the year ended december 31 , 2020 for our shop segment is net of a $ 3,842 reserve for a medicare refund we paid in january 2021. property operating expenses for the year ended december 31 , 2020 for our shop segment includes $ 1,928 of estimated penalties , compliance costs and professional fees , net of management fees reimbursable by five star , related to the medicare refund . for further information regarding this matter , see elsewhere in this annual report on form 10-k , including note 6 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k. ( 8 ) medical office and life science property occupancy data is as of december 31 , 2020 and 2019 and includes ( i ) out of service assets undergoing redevelopment , ( ii ) space which is leased but is not occupied or is being offered for sublease by tenants and ( iii ) space being fitted out for occupancy . ( 9 ) excludes data for periods prior to our ownership of certain properties , data for properties sold or classified as held for sale and data for which there was a transfer of operations during the periods presented . story_separator_special_tag 72 replace_table_token_7_th nm – not meaningful office portfolio : replace_table_token_8_th ( 1 ) consists of medical office and life science properties that we have owned and which have been in service continuously since january 1 , 2019 , including our life science property owned in a joint venture arrangement in which we own a 55 % equity interest ; excludes properties classified as held for sale or out of service undergoing redevelopment , if any . ( 2 ) prior periods exclude space remeasurements made subsequent to those periods . ( 3 ) medical office and life science property occupancy includes ( i ) out of service assets undergoing redevelopment , ( ii ) space which is leased but is not occupied or is being offered for sublease by tenants , and ( iii ) space being fitted out for occupancy . comparable property occupancy excludes out of service assets undergoing redevelopment . replace_table_token_9_th ( 1 ) consists of medical office and life science properties that we have owned and which have been in service continuously since january 1 , 2019 , including our life science property owned in a joint venture arrangement in which we own a 55 % equity interest ; excludes properties classified as held for sale or out of service undergoing redevelopment , if any . 73 rental income . rental income decreased primarily due to our disposition of 32 properties since january 1 , 2019 , assets being taken out of service and or undergoing redevelopment and a decrease in rental income at our comparable properties . rental income decreased at our comparable properties primarily due to reduced parking revenue at certain of our comparable properties related to the covid-19 pandemic and increased bad debt , partially offset by higher real estate tax and other property operating expense reimbursements at certain of our comparable properties . property operating expenses . property operating expenses consist of real estate taxes , utility expenses , insurance , management fees , salaries and benefit costs of property level personnel , repairs and maintenance expense , cleaning expense and other direct costs of operating these properties . the decrease in property operating expenses is primarily due to our disposition of 32 properties since january 1 , 2019 , partially offset by an increase in property operating expenses at our comparable properties . property operating expenses at our comparable properties increased primarily due to increases in real estate taxes and insurance expense , partially offset by decreases in utility expenses , landscaping expenses , parking expenses and other direct costs at certain of our comparable properties . net operating income . the change in noi reflects the net changes in rental income and property operating expenses described above . shop : replace_table_token_10_th ( 1 ) consists of senior living communities that we have owned and which have been operated by the same operator continuously since january 1 , 2019 ; excludes communities classified as held for sale or closed , if any . ( 2 ) average monthly rate is calculated by taking the average daily rate , which is defined as total residents fees and services divided by occupied units during the period , and multiplying it by 30 days . replace_table_token_11_th ( 1 ) consists of senior living communities that we have owned and which have been operated by the same operator continuously since january 1 , 2019 ; excludes communities classified as held for sale or closed , if any . as a result of routine monitoring protocols that are a part of five star 's compliance program activities related to medicare billing , five star discovered potentially inadequate documentation at one of our senior living communities that five star manages . this monitoring was not initiated in response to any specific complaint or allegation but rather was of the type that five star periodically undertakes to test its compliance with applicable medicare billing rules . we and five star voluntarily disclosed this matter to the oig pursuant to the oig 's provider self-disclosure protocol . in january 2021 , we and five star settled this matter with the oig and we agreed to pay approximately $ 5,763 in exchange for a customary release , but we and five star did not admit any liability . we paid that amount to the oig in january 2021. five star refunded to us $ 115 of management fees it previously received relating to the medicare payments we refunded to the oig . with respect to this settlement amount , we accrued a revenue reserve of $ 3,842 at december 31 , 2020 for historical medicare payments we received and agreed to repay to the oig and we recorded expenses of $ 1,921 for the year ended december 31 , 2020 for oig-imposed penalties . rental income . rental income decreased due to the termination of our previously existing master leases with five star . pursuant to the restructuring transaction , effective january 1 , 2020 , our previously existing master leases and management and 74 pooling agreements with five star were terminated and replaced with the five star management agreements for all of our senior living communities operated by five star . see note 6 to our consolidated financial statements included in part iv , item 15 of this annual report on form 10-k for information regarding the restructuring transaction . residents fees and services . residents fees and services are the revenues earned at our managed senior living communities . we recognize these revenues as services are provided and related fees are accrued . residents fees and services increased primarily due to the restructuring transaction and the resulting change to our management arrangement with five star for all of our senior living communities that it operates and our acquisition of one active adult rental property since january 1 , 2019 , partially offset by decreases in occupancy and average monthly rate primarily due to the impact of the covid-19

