The following table includes a breakout of our results for our same store portfolio for rental revenues, rental expenses and NOI for the three months ended September 30, 2022 as compared to the three months ended June 30, 2022, and for the nine months ended September 30, 2022 as compared to the same period in 2021:
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| | For the Three Months Ended | | | | | | | | | For the Nine Months Ended | | | | | | | |
(in thousands) | | September 30, 2022 | | June 30, 2022 | | Change | | % Change | | | September 30, 2022 | | September 30, 2021 | | Change | | % Change | |
Rental revenues: | | | | | | | | | | | | | | | | | | | | | | | | | | |
Same store operating properties | | $ | 88,437 | | | 85,001 | | | 3,436 | | | 4.0 | % | | $ | 75,279 | | $ | 71,587 | | $ | 3,692 | | | 5.2 | % |
Other properties | | | 19,878 | | | 7,793 | | | 12,085 | | | NM | | | | 207,388 | | | 37,313 | | | 170,075 | | | NM | |
Total rental revenues | | | 108,315 | | | 92,794 | | | 15,521 | | | 16.7 | % | | | 282,667 | | | 108,900 | | | 173,767 | | | NM | |
Rental expenses: | | | | | | | | | | | | | | | | | | | | | | | | | | |
Same store operating properties | | | (21,606) | | | (20,525) | | | (1,081) | | | 5.3 | % | | | (17,935) | | | (17,446) | | | (489) | | | (2.8) | % |
Other properties | | | (4,459) | | | (1,515) | | | (2,944) | | | NM | | | | (50,858) | | | (8,597) | | | (42,261) | | | NM | |
Total rental expenses | | | (26,065) | | | (22,040) | | | (4,025) | | | 18.3 | % | | | (68,793) | | | (26,043) | | | (42,750) | | | NM | |
Net operating income: | | | | | | | | | | | | | | | | | | | | | | | | | | |
Same store operating properties | | | 66,831 | | | 64,476 | | | 2,355 | | | 3.7 | % | | | 57,344 | | | 54,141 | | | 3,203 | | | 5.9 | % |
Other properties | | | 15,419 | | | 6,278 | | | 9,141 | | | NM | | | | 156,530 | | | 28,716 | | | 127,814 | | | NM | |
Total net operating income | | $ | 82,250 | | $ | 70,754 | | $ | 11,496 | | | 16.2 | % | | $ | 213,874 | | $ | 82,857 | | $ | 131,017 | | | NM | |
NM = Not meaningful
Rental Revenues. Non-same store revenues increased by $12.1 million for the three months ended September 30, 2022 as compared to the previous quarter, as a result of the addition of 39 industrial buildings we have acquired since April 1, 2022. Same store rental revenues increased by $3.4 million, or 4.0%, for the three months ended September 30, 2022 as compared to the previous quarter, primarily due to an increase in current year and prior year recoverable expenses that resulted in increases to recovery revenue, as well as increases in average occupancy and increases in rental rates.
Non-same store revenues increased by $170.1 million for the nine months ended September 30, 2022, as compared to the same period in 2021, primarily due to the addition of 176 industrial buildings that we have acquired since January 1, 2021. Same store rental revenues increased by $3.7 million, or 5.2%, for the nine months ended September 30, 2022 as compared to the same period in 2021, primarily due to the increase in rental rates since September 30, 2021, partially offset by a small decrease in average occupancy.
Rental Expenses. Non-same store rental expenses increased by $2.9 million for the three months ended September 30, 2022, as compared to the previous quarter, due to the buildings acquired since April 1, 2022. Same store rental expenses increased $1.1 million, or 5.3%, for the three months ended September 30, 2022 as compared to the previous quarter, due to an increase in property and franchise taxes associated with certain of our properties and an increase in recoverable expenses.
Non-same store rental expenses increased by $42.3 million for the nine months ended September 30, 2022 as compared to the same period in 2021, primarily due to the significant growth in our portfolio. Same store rental expenses increased by $0.5 million, or 2.8%, for the nine months ended September 30, 2022 as compared to the same period in 2021, primarily due to the successful resolution of a prior year tax appeal related to one of our properties and an increase in franchise taxes, both resulting in an increase in recoverable expenses, partially offset by a decrease in certain seasonal costs.
Generally, we are prohibited by our charter from incurring total operating expenses which, at the end of the four preceding fiscal quarters exceeds the greater of: (i) 2.0% of our average invested assets, or (ii) 25.0% of our net income determined without reduction for any additions to reserves for depreciation, bad debts or other similar non-cash reserves and excluding any gain from the sale of our assets for that period (the “2%/25% Limitation”). For these purposes, total operating expenses exclude rental expenses, real estate-related depreciation and amortization expense, interest expense, acquisition expenses, taxes and impairments. Our charter requires that we calculate the figures used in determining whether operating expenses have exceeded the 2%/25% Limitation in accordance with GAAP applied on a consistent basis. Notwithstanding the above, we may incur total operating expenses in excess of this limitation if a majority of our independent directors determines that such excess expenses are justified based on unusual and non-recurring factors. Our total operating expenses exceeded the 2%/25% Limitation as of the four fiscal quarters ended September 30, 2022. All of our independent directors determined that the excess expenses were justified based upon a review of unusual and non-recurring factors, including but not limited to: the strong performance of our portfolio driven by the continued demand in the industrial property sector and the resulting significant growth in our NAV and total return generated for the period which, in combination with the incentive distributions we received from the BTC II Partnership in the fourth quarter of 2021, drove a significant increase in the performance participation allocation. Other factors considered include our continued, strong capital raise and the timing of our deployment during the period, including the acquisition of 40 industrial properties in the fourth quarter of 2021, the BTC II Partnership Transaction in the first quarter of 2022, and the acquisition of 38 industrial properties in the second quarter of 2022. The calculation of the performance participation allocation is based in part on our calculation of NAV, which takes into account any increases or decreases in the fair market value of our investments in real estate, meaning that generally, as NAV increases and the corresponding total return generated