In May 2014, the FASB issued ASC 606, Revenue From Contracts With Customers, originally effective for public business entities with annual reporting periods beginning after December 15, 2016. On August 12, 2015, the FASB issued an ASU, Revenue From Contracts With Customers (Topic 606): Deferral of the Effective Date, which deferred the effective date of ASC 606 for one year. ASC 606 provides accounting guidance related to revenue from contracts with customers. For public business entities, ASC 606 was effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company has adopted ASC 606 and determined that the adoption has not had a material impact on its consolidated financial statements and disclosures.
RESULTS OF OPERATIONS
Results comparisons are for the three and nine months ended September 30, 2018 and 2017:
Investment Income
For the three and nine months ended September 30, 2018, gross investment income totaled $11.0 million and $29.8 million, respectively. For the three and nine months ended September 30, 2017, gross investment income totaled $8.0 million and $23.1 million, respectively. The increase in gross investment income for the year over year three and nine month periods was primarily due to average portfolio growth, including from our investment in NMC, as well as our portfolio yield increasing year over year.
Expenses
Net expenses totaled $5.3 million and $12.8 million, respectively, for the three and nine months ended September 30, 2018, of which $2.6 million and $5.9 million, respectively, were gross base management fees and gross performance-based incentive fees and $2.0 million and $5.2 million, respectively, were interest and other credit facility expenses. Over the same periods, $0.0 million and $0.7 million, respectively, of performance-based incentive fees were waived. Administrative services and other general and administrative expenses totaled $0.7 million and $2.4 million, respectively, for the three and nine months ended September 30, 2018. Net expenses totaled $2.3 million and $6.2 million, respectively, for the three and nine months ended September 30, 2017, of which $1.2 million and $3.3 million, respectively, were gross base management fees and gross performance-based incentive fees and $1.0 million and $2.7 million, respectively, were interest and other credit facility expenses. Over the same periods, $0.5 million and $2.0 million, respectively, of base management fees were waived and $0.2 million and $0.4 million, respectively, of performance-based incentive fees were waived. Administrative services and other general and administrative expenses totaled $0.9 million and $2.6 million, respectively, for the three and nine months ended September 30, 2017. Expenses generally consist of management fees, performance-based incentive fees, administrative services expenses, insurance, legal expenses, directors’ expenses, audit and tax expenses, transfer agent fees and expenses, and other general and administrative expenses. Interest and other credit facility expenses generally consist of interest, unused fees, agency fees and loan origination fees, if any, among others. For the three and nine month periods, the increase in net expenses year over year is primarily due to higher interest, incentive and management fee expense on a larger, higher yielding portfolio as compared to the year ago periods.
Net Investment Income
The Company’s net investment income totaled $5.8 million and $17.1 million, or $0.36 and $1.06, per average share, respectively, for the three and nine months ended September 30, 2018. The Company’s net investment income totaled $5.7 million and $17.0 million, or $0.35 and $1.06, per average share, respectively, for the three and nine months ended September 30, 2017.
Net Realized Gain
The Company had investment sales and prepayments totaling approximately $84.2 million and $135.2 million, respectively, for the three and nine months ended September 30, 2018. Net realized losses over
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