business portfolio and investment activity in general , our investments in debt securities have a term of no more than seven years , accrue interest at variable rates ( generally based on the one-month libor ) and , to a lesser extent , at fixed rates . we seek debt instruments that pay interest monthly or , at a minimum , quarterly , have a success fee or deferred interest provision and are primarily interest only with all principal and any accrued but unpaid interest due at maturity . generally , success fees accrue at a set rate and are contractually due upon a change of control of a portfolio company , typically from an exit or sale . some debt securities have deferred interest whereby some portion of the interest payment is added to the principal balance so that the interest is paid , together with the principal , at maturity . this form of deferred interest is often called pik interest . 41 typically , our equity investments consist of common stock , preferred stock , limited liability company interests , or warrants to purchase the foregoing . often , these equity investments occur in connection with our original investment , recapitalizing a business , or refinancing existing debt . during the year ended september 30 , 2017 , we invested $ 99.2 million in eleven new portfolio companies and extended $ 17.6 million of investments to existing portfolio companies . in addition , during the year ended september 30 , 2017 , we exited nine portfolio companies through sales and early payoffs . we received a total of $ 83.4 million in combined net proceeds and principal repayments from the aforementioned portfolio company exits as well as existing portfolio companies during the year ended september 30 , 2017. this activity resulted in a net increase in our overall portfolio by two portfolio companies to 47 and a net increase of 7.8 % in our portfolio at cost since september 30 , 2016. we intend to continue to make new conservative investments in businesses with steady cash flows . we are focused on building our pipeline and making investments that meet our objectives and strategies and that provide appropriate returns , in light of the accompanying risks . from our initial public offering in august 2001 and through september 30 , 2017 , we have made 470 different loans to , or investments in , 217 companies for a total of approximately $ 1.7 billion , before giving effect to principal repayments on investments and divestitures . during the year ended september 30 , 2017 , the following significant transactions occurred : in october 2016 , rp crown parent , llc paid off at par for net proceeds of $ 2.0 million . in october 2016 , our $ 3.9 million secured first lien debt investment in vertellus specialties , inc. was restructured . as a result of the restructure , we received a new $ 1.1 million secured second lien debt investment in vertellus holdings llc and common equity with a cost basis of $ 3.0 million . in november 2016 , we completed the sale of substantially all the assets of rbc acquisition corp. ( rbc ) for net proceeds of $ 36.3 million , which resulted in a realized loss of $ 2.3 million . in connection with the sale , we received success fee income of $ 1.1 million and net receivables of $ 1.5 million , which are recorded within other assets , net . in november 2016 , we invested $ 5.2 million in sea link international irb , inc. through secured second lien debt and equity . in december 2016 , we sold our investment in behrens manufacturing , llc ( behrens ) , which resulted in success fee income of $ 0.4 million and a realized gain of $ 2.5 million . in connection with the sale , we received net cash proceeds of $ 8.2 million , including the repayment of our debt investment of $ 4.3 million at par . in december 2016 , we invested $ 7.0 million in vacation rental pros property management , llc through secured second lien debt . in december 2016 , autoparts holdings limited paid off at par for proceeds of $ 0.7 million . in december 2016 , we invested $ 5.0 million in ldiscovery , llc through secured second lien debt . in february 2017 , we invested $ 10.0 million in belnick , inc. through secured second lien debt . in february 2017 , we invested $ 29.0 million in netfortris corp. through secured first lien debt . in february 2017 , vitera healthcare solutions , llc paid off at par for net proceeds of $ 4.5 million . in march 2017 , lcr contractors , llc paid off at par for net cash proceeds of $ 8.6 million . in connection with the payoff , we received a prepayment fee of $ 0.2 million . in april 2017 , we invested $ 22.0 million in hb capital resources , ltd. through secured second lien debt . in may 2017 , we invested an additional $ 4.1 million in an existing portfolio company , lignetics , inc. , through secured second lien debt and equity , to support an acquisition . 42 in may 2017 , we invested $ 4.0 million in keystone acquisition corp. through secured second lien debt . in june 2017 , we invested $ 3.0 million in medical solutions holdings , inc. through secured second lien debt . in july 2017 , our loan to sourcehov , llc was paid off for net proceeds of $ 4.8 million , resulting in a realized loss of $ 0.2 million . in august 2017 , we invested $ 12.5 million in el academies , inc. through secured first lien debt and equity . story_separator_special_tag during the year ended september 30 , 2016 , we reversed $ 0.1 million of unrealized depreciation related to the expiration of our interest rate cap agreement in january 2016 . 49 comparison of the year ended september 30 , 2016 to the year ended september 30 , 2015 replace_table_token_15_th investment income interest income increased by 0.9 % for the year ended september 30 , 2016 , as compared to the prior year . this increase was due primarily to an increase in the weighted average yield on our interest-bearing portfolio partially offset by a slight decrease in the principal balance of our interest-bearing investment portfolio outstanding during the year . the weighted average yield on our interest-bearing investments is based on the current stated interest rate on interest-bearing investments which increased to 11.1 % for the year ended september 30 , 2016 compared to 10.9 % for the year ended september 30 , 2015 , inclusive of any allowances on interest receivables made during those periods . the weighted average principal balance of our interest-bearing investment portfolio during the year ended september 30 , 2016 , was $ 317.0 million , compared to $ 319.1 million for the prior year , a decrease of $ 2.1 million , or 0.1 % . as of september 30 , 2016 , two portfolio companies , sunshine and vertellus specialties , inc. , were either fully or partially on non-accrual status , with an aggregate debt cost basis of approximately $ 26.5 million , or 7.7 % of the cost basis of all debt investments in our portfolio . as of september 30 , 2015 , two portfolio companies , sunshine and heartland , were either fully or partially on non-accrual status , with an aggregate debt cost basis of approximately $ 26.4 million , or 7.1 % of the cost basis of all debt investments in our portfolio . other income increased by 23.1 % during the year ended september 30 , 2016 , as compared to the prior year . for the year ended september 30 , 2016 , other income consisted primarily of $ 3.4 million in success fees recognized , $ 0.3 million in dividend income received , and $ 0.2 million in prepayment fees received . for the year ended september 30 , 2015 , other income consisted primarily of $ 1.9 million in success fees recognized , $ 0.9 million in dividend income , and $ 0.3 million in settlement fees . 50 the following tables list the investment income for our five largest portfolio company investments at fair value during the respective years : replace_table_token_16_th ( a ) new investment during applicable period . expenses expenses , net of credits from the adviser , decreased for the year ended september 30 , 2016 , by 3.6 % as compared to the prior year . this decrease was primarily due to decreases in our net base management fees to the advisor and interest expense on borrowings , partially offset by an increase in the net incentive fee to the adviser . interest expense decreased by $ 0.9 million , or 24.3 % , during the year ended september 30 , 2016 , as compared to the prior year , primarily due to decreased borrowings outstanding throughout the period on our credit facility . the weighted average balance outstanding on our credit facility during the year ended september 30 , 2016 , was approximately $ 64.0 million , as compared to $ 92.5 million in the prior year period , a decrease of 30.8 % . net base management fee earned by the adviser decreased by $ 0.6 million , or 10.5 % , during the year ended september 30 , 2016 , as compared to the prior year period , resulting from a decrease in the average total assets outstanding and a decrease in the annual base management fee from 2.0 % to 1.75 % , which was effective july 1 , 2015. the base management , loan servicing and incentive fees , and associated non-contractual , unconditional and irrevocable credits , are computed quarterly , as described under transactions with the adviser in note 4 related party transactions of the accompanying notes to consolidated financial statements and are summarized in the following table : 51 replace_table_token_17_th ( a ) average total assets subject to the base management fee is defined as total assets , including investments made with proceeds of borrowings , less any uninvested cash or cash equivalents resulting from borrowings , valued at the end of the four most recently completed quarters within the respective years and adjusted appropriately for any share issuances or repurchases during the applicable year . ( b ) reflected , on a gross basis , as a line item on our accompanying consolidated statement of operations located elsewhere in this annual report on form 10-k. realized loss and unrealized appreciation net realized loss on investments for the year ended september 30 , 2016 , we recorded a net realized gain on investments of $ 7.2 million , which resulted primarily from the sales of funko , spl , westland , and ashland for a combined realized gain of $ 18.7 million and net proceeds of $ 35.4 million . this realized gain was partially offset by a combined realized loss of $ 11.7 million recognized from the sale of heartland and the restructures of targus and precision during the year ended september 30 , 2016. we also recognized a realized loss of $ 0.6 million during the year ended september 30 , 2016 related to a settlement associated with wp evenflo group holdings , inc. , which we had previously exited at a realized gain of $ 1.0 million in september 2014. for the year ended september 30 , 2015 , we recorded a net realized loss on investments of $ 34.2 million , which resulted primarily from the sales of midwest metal distribution , inc. ( midwest

liquidity and capital resources operating activities our cash flows from operating activities are primarily generated from the interest payments on debt securities that we receive from our portfolio companies , as well as net proceeds received through repayments or sales of our investments . we utilize this cash primarily to fund new investments , make interest payments on our credit facility , make distributions to our stockholders , pay management and administrative fees to the adviser and administrator , and for other operating expenses . net cash used in operating activities for the year ended september 30 , 2017 was $ 12.9 million as compared to net cash provided by operating activities of $ 60.0 million for the year ended september 30 , 2016. the change was primarily due to an increase in purchases of investments and a decrease in principal repayments on investments and net proceeds from sale of investments period over period . purchases of investments were $ 112.1 million during the year ended september 30 , 2017 compared to $ 80.0 million during the prior year period . repayments and net proceeds from sales were $ 83.4 million during the year ended september 30 , 2017 compared to $ 121.1 million during the prior year period . as of september 30 , 2017 , we had loans to , syndicated participations in or equity investments in 47 private companies , with an aggregate cost basis of approximately $ 411.4 million . as of september 30 , 2016 , we had loans to , syndicated participations in or equity investments in 45 private companies , with an aggregate cost basis of approximately $ 381.8 million . the following table summarizes our total portfolio investment activity during the years ended september 30 , 2017 and 2016 : replace_table_token_20_th ( a ) pik interest is a non-cash source of income and is calculated at the contractual rate stated in a loan agreement and added to the principal balance of a loan .


 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.
     ```liquidity and capital resources operating activities our cash flows from operating activities are primarily generated from the interest payments on debt securities that we receive from our portfolio companies , as well as net proceeds received through repayments or sales of our investments . we utilize this cash primarily to fund new investments , make interest payments on our credit facility , make distributions to our stockholders , pay management and administrative fees to the adviser and administrator , and for other operating expenses . net cash used in operating activities for the year ended september 30 , 2017 was $ 12.9 million as compared to net cash provided by operating activities of $ 60.0 million for the year ended september 30 , 2016. the change was primarily due to an increase in purchases of investments and a decrease in principal repayments on investments and net proceeds from sale of investments period over period . purchases of investments were $ 112.1 million during the year ended september 30 , 2017 compared to $ 80.0 million during the prior year period . repayments and net proceeds from sales were $ 83.4 million during the year ended september 30 , 2017 compared to $ 121.1 million during the prior year period . as of september 30 , 2017 , we had loans to , syndicated participations in or equity investments in 47 private companies , with an aggregate cost basis of approximately $ 411.4 million . as of september 30 , 2016 , we had loans to , syndicated participations in or equity investments in 45 private companies , with an aggregate cost basis of approximately $ 381.8 million . the following table summarizes our total portfolio investment activity during the years ended september 30 , 2017 and 2016 : replace_table_token_20_th ( a ) pik interest is a non-cash source of income and is calculated at the contractual rate stated in a loan agreement and added to the principal balance of a loan .
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 Suspicious Activity Report : business portfolio and investment activity in general , our investments in debt securities have a term of no more than seven years , accrue interest at variable rates ( generally based on the one-month libor ) and , to a lesser extent , at fixed rates . we seek debt instruments that pay interest monthly or , at a minimum , quarterly , have a success fee or deferred interest provision and are primarily interest only with all principal and any accrued but unpaid interest due at maturity . generally , success fees accrue at a set rate and are contractually due upon a change of control of a portfolio company , typically from an exit or sale . some debt securities have deferred interest whereby some portion of the interest payment is added to the principal balance so that the interest is paid , together with the principal , at maturity . this form of deferred interest is often called pik interest . 41 typically , our equity investments consist of common stock , preferred stock , limited liability company interests , or warrants to purchase the foregoing . often , these equity investments occur in connection with our original investment , recapitalizing a business , or refinancing existing debt . during the year ended september 30 , 2017 , we invested $ 99.2 million in eleven new portfolio companies and extended $ 17.6 million of investments to existing portfolio companies . in addition , during the year ended september 30 , 2017 , we exited nine portfolio companies through sales and early payoffs . we received a total of $ 83.4 million in combined net proceeds and principal repayments from the aforementioned portfolio company exits as well as existing portfolio companies during the year ended september 30 , 2017. this activity resulted in a net increase in our overall portfolio by two portfolio companies to 47 and a net increase of 7.8 % in our portfolio at cost since september 30 , 2016. we intend to continue to make new conservative investments in businesses with steady cash flows . we are focused on building our pipeline and making investments that meet our objectives and strategies and that provide appropriate returns , in light of the accompanying risks . from our initial public offering in august 2001 and through september 30 , 2017 , we have made 470 different loans to , or investments in , 217 companies for a total of approximately $ 1.7 billion , before giving effect to principal repayments on investments and divestitures . during the year ended september 30 , 2017 , the following significant transactions occurred : in october 2016 , rp crown parent , llc paid off at par for net proceeds of $ 2.0 million . in october 2016 , our $ 3.9 million secured first lien debt investment in vertellus specialties , inc. was restructured . as a result of the restructure , we received a new $ 1.1 million secured second lien debt investment in vertellus holdings llc and common equity with a cost basis of $ 3.0 million . in november 2016 , we completed the sale of substantially all the assets of rbc acquisition corp. ( rbc ) for net proceeds of $ 36.3 million , which resulted in a realized loss of $ 2.3 million . in connection with the sale , we received success fee income of $ 1.1 million and net receivables of $ 1.5 million , which are recorded within other assets , net . in november 2016 , we invested $ 5.2 million in sea link international irb , inc. through secured second lien debt and equity . in december 2016 , we sold our investment in behrens manufacturing , llc ( behrens ) , which resulted in success fee income of $ 0.4 million and a realized gain of $ 2.5 million . in connection with the sale , we received net cash proceeds of $ 8.2 million , including the repayment of our debt investment of $ 4.3 million at par . in december 2016 , we invested $ 7.0 million in vacation rental pros property management , llc through secured second lien debt . in december 2016 , autoparts holdings limited paid off at par for proceeds of $ 0.7 million . in december 2016 , we invested $ 5.0 million in ldiscovery , llc through secured second lien debt . in february 2017 , we invested $ 10.0 million in belnick , inc. through secured second lien debt . in february 2017 , we invested $ 29.0 million in netfortris corp. through secured first lien debt . in february 2017 , vitera healthcare solutions , llc paid off at par for net proceeds of $ 4.5 million . in march 2017 , lcr contractors , llc paid off at par for net cash proceeds of $ 8.6 million . in connection with the payoff , we received a prepayment fee of $ 0.2 million . in april 2017 , we invested $ 22.0 million in hb capital resources , ltd. through secured second lien debt . in may 2017 , we invested an additional $ 4.1 million in an existing portfolio company , lignetics , inc. , through secured second lien debt and equity , to support an acquisition . 42 in may 2017 , we invested $ 4.0 million in keystone acquisition corp. through secured second lien debt . in june 2017 , we invested $ 3.0 million in medical solutions holdings , inc. through secured second lien debt . in july 2017 , our loan to sourcehov , llc was paid off for net proceeds of $ 4.8 million , resulting in a realized loss of $ 0.2 million . in august 2017 , we invested $ 12.5 million in el academies , inc. through secured first lien debt and equity . story_separator_special_tag during the year ended september 30 , 2016 , we reversed $ 0.1 million of unrealized depreciation related to the expiration of our interest rate cap agreement in january 2016 . 49 comparison of the year ended september 30 , 2016 to the year ended september 30 , 2015 replace_table_token_15_th investment income interest income increased by 0.9 % for the year ended september 30 , 2016 , as compared to the prior year . this increase was due primarily to an increase in the weighted average yield on our interest-bearing portfolio partially offset by a slight decrease in the principal balance of our interest-bearing investment portfolio outstanding during the year . the weighted average yield on our interest-bearing investments is based on the current stated interest rate on interest-bearing investments which increased to 11.1 % for the year ended september 30 , 2016 compared to 10.9 % for the year ended september 30 , 2015 , inclusive of any allowances on interest receivables made during those periods . the weighted average principal balance of our interest-bearing investment portfolio during the year ended september 30 , 2016 , was $ 317.0 million , compared to $ 319.1 million for the prior year , a decrease of $ 2.1 million , or 0.1 % . as of september 30 , 2016 , two portfolio companies , sunshine and vertellus specialties , inc. , were either fully or partially on non-accrual status , with an aggregate debt cost basis of approximately $ 26.5 million , or 7.7 % of the cost basis of all debt investments in our portfolio . as of september 30 , 2015 , two portfolio companies , sunshine and heartland , were either fully or partially on non-accrual status , with an aggregate debt cost basis of approximately $ 26.4 million , or 7.1 % of the cost basis of all debt investments in our portfolio . other income increased by 23.1 % during the year ended september 30 , 2016 , as compared to the prior year . for the year ended september 30 , 2016 , other income consisted primarily of $ 3.4 million in success fees recognized , $ 0.3 million in dividend income received , and $ 0.2 million in prepayment fees received . for the year ended september 30 , 2015 , other income consisted primarily of $ 1.9 million in success fees recognized , $ 0.9 million in dividend income , and $ 0.3 million in settlement fees . 50 the following tables list the investment income for our five largest portfolio company investments at fair value during the respective years : replace_table_token_16_th ( a ) new investment during applicable period . expenses expenses , net of credits from the adviser , decreased for the year ended september 30 , 2016 , by 3.6 % as compared to the prior year . this decrease was primarily due to decreases in our net base management fees to the advisor and interest expense on borrowings , partially offset by an increase in the net incentive fee to the adviser . interest expense decreased by $ 0.9 million , or 24.3 % , during the year ended september 30 , 2016 , as compared to the prior year , primarily due to decreased borrowings outstanding throughout the period on our credit facility . the weighted average balance outstanding on our credit facility during the year ended september 30 , 2016 , was approximately $ 64.0 million , as compared to $ 92.5 million in the prior year period , a decrease of 30.8 % . net base management fee earned by the adviser decreased by $ 0.6 million , or 10.5 % , during the year ended september 30 , 2016 , as compared to the prior year period , resulting from a decrease in the average total assets outstanding and a decrease in the annual base management fee from 2.0 % to 1.75 % , which was effective july 1 , 2015. the base management , loan servicing and incentive fees , and associated non-contractual , unconditional and irrevocable credits , are computed quarterly , as described under transactions with the adviser in note 4 related party transactions of the accompanying notes to consolidated financial statements and are summarized in the following table : 51 replace_table_token_17_th ( a ) average total assets subject to the base management fee is defined as total assets , including investments made with proceeds of borrowings , less any uninvested cash or cash equivalents resulting from borrowings , valued at the end of the four most recently completed quarters within the respective years and adjusted appropriately for any share issuances or repurchases during the applicable year . ( b ) reflected , on a gross basis , as a line item on our accompanying consolidated statement of operations located elsewhere in this annual report on form 10-k. realized loss and unrealized appreciation net realized loss on investments for the year ended september 30 , 2016 , we recorded a net realized gain on investments of $ 7.2 million , which resulted primarily from the sales of funko , spl , westland , and ashland for a combined realized gain of $ 18.7 million and net proceeds of $ 35.4 million . this realized gain was partially offset by a combined realized loss of $ 11.7 million recognized from the sale of heartland and the restructures of targus and precision during the year ended september 30 , 2016. we also recognized a realized loss of $ 0.6 million during the year ended september 30 , 2016 related to a settlement associated with wp evenflo group holdings , inc. , which we had previously exited at a realized gain of $ 1.0 million in september 2014. for the year ended september 30 , 2015 , we recorded a net realized loss on investments of $ 34.2 million , which resulted primarily from the sales of midwest metal distribution , inc. ( midwest

