Common use of Portfolio Composition Clause in Contracts

Portfolio Composition. Our portfolio companies are primarily privately held companies and public companies which are active in the drug discovery and development, energy technology, internet consumer and business services, medical device and equipment, software, drug delivery, specialty pharmaceuticals, communications and networking, media/content/info, healthcare services, information services, surgical devices, semiconductors, biotechnology tools, consumer and business products, diagnostic and electronics and computer hardware industry sectors. These sectors are characterized by high margins, high growth rates, consolidation and product and market extension opportunities. Value for companies in these sectors is often vested in intangible assets and intellectual property. As of March 31, 2014, approximately 64.9% of the fair value of our portfolio was composed of investments in four industries: 23.2% was composed of investments in the drug discovery and development industry, 18.7% was composed of investments in the energy technology industry, 11.9% was composed of investments in the internet consumer and business services industry and 11.1% was composed of investments in the medical device and equipment industry. The following table shows the fair value of our portfolio by industry sector at March 31, 2014 (unaudited) and December 31, 2013: March 31, 2014 December 31, 2013 (in thousands) Investments at Fair Value Percentage of Total Portfolio Investments at Fair Value Percentage of Total Portfolio Drug Discovery & Development $ 206,535 23.2% $ 219,169 24.1% Energy Technology 166,482 18.7% 164,466 18.1% Internet Consumer & Business Services 105,964 11.9% 122,073 13.4% Medical Devices & Equipment 99,061 11.1% 103,614 11.4% Software 79,077 8.9% 65,218 7.2% Drug Delivery 63,335 7.1% 62,022 6.8% Specialty Pharmaceuticals 40,217 4.5% 20,055 2.2% Communications & Networking 35,526 4.0% 35,979 4.0% Media/Content/Info 29,447 3.3% 8,679 1.0% Healthcare Services, Other 20,626 2.3% 29,080 3.2% Information Services 15,102 1.7% 46,565 5.1% Surgical Devices 10,353 1.1% 10,307 1.0% Semiconductors 9,464 1.1% 4,685 0.5% Biotechnology Tools 4,541 0.5% 5,275 0.6% Consumer & Business Products 3,282 0.4% 2,995 0.3% Diagnostic 858 0.1% 902 0.1% Electronics & Computer Hardware 792 0.1% 9,211 1.0% $ 890,662 100.0% $ 910,295 100.0% Industry and sector concentrations vary as new loans are recorded and loans pay off. Loan revenue, consisting of interest, fees, and recognition of gains on equity and equity- related interests, can fluctuate materially when a loan is paid off or a related warrant or equity interest is sold. Revenue recognition in any given year can be highly concentrated among several portfolio companies. For the three-months ended March 31, 2014 and the year ended December 31, 2013, our ten largest portfolio companies represented approximately 29.5% and 29.3% of the total fair value of our investments in portfolio companies, respectively. At both March 31, 2014 and December 31, 2013, we had one investment that represented 5% or more of our net assets. At March 31, 2014, we had five equity investments representing approximately 71.0% of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity investments. At December 31, 2013, we had six equity investments which represented approximately 75.7% of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity investments. As of March 31, 2014, 100% of our debt investments were in a senior secured first lien position, and approximately 98.0% of the debt investment portfolio was priced at floating interest rates or floating interest rates with a Prime-or LIBOR-based interest rate floor. As a result, we believe we are well positioned to benefit should market interest rates increase. Our investments in senior secured debt with warrants have equity enhancement features, typically in the form of warrants or other equity-related securities designed to provide us with an opportunity for capital appreciation. Our warrant coverage generally ranges from 3% to 20% of the principal amount invested in a portfolio company, with a strike price generally equal to the most recent equity financing round. As of March 31, 2014, we held warrants in 107 portfolio companies, with a fair value of approximately $23.6 million. The fair value of our warrant portfolio decreased by approximately 33.7%, as compared to a fair value of $35.6 million at December 31, 2013 primarily related to the reversal of unrealized appreciation related to the exercise of our warrant positions in Neuralstem, Inc. ($751,000) and Box, Inc. ($8.3 million) to preferred stock. Our existing warrant holdings currently would require us to invest approximately $68.6 million to exercise such warrants as of March 31, 2014. Warrants may appreciate or depreciate in value depending largely upon the underlying portfolio company’s performance and overall market conditions. Of the warrants which we have monetized since inception, we have realized warrant gain multiples in the range of approximately 1.01x to 14.91x based on the historical rate of return on our investments. However, our warrants may not appreciate in value and, in fact, may decline in value. Accordingly, we may not be able to realize gains from our warrant portfolio.

Portfolio Composition. Our portfolio companies are primarily privately held companies and public companies which are active in the drug discovery and & development, energy technologysoftware, internet consumer and & business services, medical device and equipment, software, drug delivery, specialty pharmaceuticals, communications and networking, media/content/info, sustainable and renewable technology, medical devices & equipment, drug delivery, healthcare services, specialty pharmaceuticals, information services, consumer & business products, surgical devices, semiconductors, electronics & computer hardware, communications & networking, biotechnology tools, consumer and business products, diagnostic and electronics and computer hardware diversified financial services industry sectors. These sectors are characterized by high margins, high growth rates, consolidation and product and market extension opportunities. Value for companies in these sectors is often vested in intangible assets and intellectual property. As of March December 31, 20142018, approximately 64.987.8% of the fair value of our portfolio was composed of investments in four five industries: 23.229.2% was composed of investments in the software industry, 28.7% was composed of investments in the drug discovery and development industry, 18.7% was composed of investments in the energy technology industry, 11.917.5% was composed of investments in the internet consumer and business services industry and 11.1industry, 6.5% was composed of investments in the medical device devices and equipment industry, and 5.9% was composed of investments in the sustainable and renewable technology industry. The following table shows the fair value of our portfolio by industry sector at March December 31, 2014 (unaudited) 2018 and December 31, 20132017: March 31, 2014 December 31, 2013 (in thousands) Investments at Fair Value Percentage of Total Portfolio Investments at Fair Value Percentage of Total Portfolio Software $ 548,952 29.2% $ 360,123 23.4% Drug Discovery & Development $ 206,535 23.2539,977 28.7% $ 219,169 24.1% Energy Technology 166,482 18.7% 164,466 18.1369,173 23.9% Internet Consumer & Business Services 105,964 11.9329,512 17.5% 122,073 13.4154,909 10.0% Medical Devices & Equipment 99,061 11.1121,420 6.5% 103,614 11.494,595 6.1% Software 79,077 8.9Sustainable and Renewable Technology 110,303 5.9% 65,218 7.2118,432 7.7% Healthcare Services, Other 60,142 3.2% 72,337 4.7% Drug Delivery 63,335 7.1% 62,022 6.8% Specialty Pharmaceuticals 40,217 4.5% 20,055 40,519 2.2% Communications & Networking 35,526 4.091,214 5.9% 35,979 4.0Diversified Financial Services 39,491 2.1% — 0.0% Information Services 30,940 1.6% 24,618 1.6% Media/Content/Info 29,447 3.321,666 1.2% 8,679 1.0152,998 9.9% Healthcare Services, Other 20,626 2.3Electronics & Computer Hardware 15,763 0.8% 29,080 3.2% Information Services 15,102 1.7% 46,565 5.1% Surgical Devices 10,353 1.1% 10,307 1.0% Semiconductors 9,464 1.1% 4,685 0.59,982 0.6% Biotechnology Tools 4,541 0.56,279 0.3% 5,275 0.65,604 0.4% Consumer & Business Products 3,282 6,179 0.3% 19,792 1.3% Communications & Networking 4,871 0.3% 6,649 0.4% 2,995 0.3Surgical Devices 3,088 0.2% 13,161 0.9% Semiconductors 899 0.0% 10,406 0.7% Diagnostic 858 348 0.0% 720 0.1% 902 0.1Specialty Pharmaceuticals 24 0.0% Electronics & Computer Hardware 792 0.137,501 2.4% 9,211 1.0% Total $ 890,662 1,880,373 100.0% $ 910,295 1,542,214 100.0% Industry and sector concentrations vary as new loans are recorded and loans pay off. Loan revenue, consisting of interest, fees, and recognition of gains on equity and equity- warrants or other equity-related interests, can fluctuate materially when a loan is paid off or a related warrant or equity interest is sold. Revenue recognition in any given year can be highly concentrated among in several portfolio companies. For the three-months ended March 31, 2014 and the year years ended December 31, 20132018 and 2017, our ten largest portfolio companies represented approximately 29.528.2% and 29.334.6% of the total fair value of our investments in portfolio companies, respectively. At both March December 31, 2014 2018 and December 31, 20132017, we had one investment seven investments that represented 5% or more of our net assets. At March December 31, 20142018 and December 31, 2017, we had five and nine equity investments representing approximately 71.053.0% and 67.1%, respectively, of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity investments. At December 31, 2013, we had six equity investments which represented approximately 75.7No single portfolio investment represents more than 10% of the total fair value of our equity investmentstotal investments as of December 31, 2018 and each represented 5% or more of the total fair value of our equity investments2017. As of March December 31, 20142018, 100% of our debt investments were in a senior secured first lien position, and approximately 98.097.3% of the debt investment portfolio was priced at floating interest rates or floating interest rates with a Prime-Prime or LIBOR-LIBOR- based interest rate floor. As a result, we believe we are well positioned to benefit should market interest rates increasecontinue to rise. In most cases, we collateralize our investments by obtaining a first priority security interest in a portfolio company’s assets, which may include its intellectual property. In other cases, we may obtain a negative pledge covering a company’s intellectual property. As of December 31, 2018, approximately 85.3% of our debt investments were in a senior secured first lien position, with 48.5% secured by a first priority security in all of the assets of the portfolio company, including its intellectual property, 28.8% secured by a first priority security in all of the assets of the portfolio company and the portfolio company was prohibited from pledging or encumbering its intellectual property. 1.1% of our debt investments were senior secured by the equipment of the portfolio company, and 6.9% were in a first lien “last-out” senior secured position with security interest in all of the assets of the portfolio company, whereby the “last-out” loans will be subordinated to the“first-out” portion of the unitranche loan in a liquidation, sale or other disposition. Another 13.8% of our debt investments were secured by a second priority security interest in all of the portfolio company’s assets, and 0.9% were unsecured. Our investments in senior secured debt with warrants have detachable equity enhancement features, typically in the form of warrants or other equity-related securities designed to provide us with an opportunity for capital appreciation. These features are treated as original issue discount and are accreted into interest income over the term of the loan as a yield enhancement. Our warrant coverage generally ranges from 3% to 20% of the principal amount invested in a portfolio company, with a strike price generally equal to the most recent equity financing round. As of March December 31, 20142018, we held warrants in 107 129 portfolio companies, with a fair value of approximately $23.6 26.7 million. The fair value of our warrant portfolio decreased by approximately 33.7%$10.1 million, as compared to a fair value of $35.6 36.8 million at December 31, 2013 2017, primarily related to a slight decrease in portfolio companies and valuation of the reversal of unrealized appreciation related to the exercise of our warrant positions in Neuralstem, Inc. ($751,000) and Box, Inc. ($8.3 million) to preferred stockportfolio. Our existing warrant holdings currently would require us to invest approximately $68.6 78.7 million to exercise such warrants as of March December 31, 20142018. Warrants may appreciate or depreciate in value depending largely upon the underlying portfolio company’s performance and overall market conditions. Of the warrants which that we have monetized since inception, we have realized warrant gain multiples in the range of approximately 1.01x 1.02x to 14.91x 29.06x based on the historical rate of return on our investments. However, our warrants may not appreciate in value and, in fact, may decline in value. Accordingly, we may not be able to realize gains experience losses from our warrant portfolio. We use an investment grading system, which grades each debt investment on a scale of 1 to 5, to characterize and monitor our expected level of risk on the debt investments in our portfolio with 1 being the highest quality. The following table shows the distribution of our outstanding debt investments on the 1 to 5 investment grading scale at fair value as of December 31, 2018 and 2017, respectively: (in thousands) December 31, 2018 December 31, 2017 Investment Grading Number ofCompanies Debt Investments at Fair Value Percentage of Total Portfolio Number ofCompanies Debt Investments at Fair Value Percentage of Total Portfolio 1 13 $ 311,597 18.0% 12 $ 345,191 24.4% 2 43 885,123 51.1% 32 583,017 41.2% 3 25 474,926 27.3% 32 443,775 31.3% 4 7 60,267 3.5% 4 41,744 2.9% 5 2 1,579 0.1% 5 2,257 0.2% 90 $ 1,733,492 100.0% 85 $ 1,415,984 100.0% As of December 31, 2018, our debt investments had a weighted average investment grading of 2.18 on a cost basis, as compared to 2.17 at December 31, 2017. Our policy is to lower the grading on our portfolio companies as they approach the point in time when they will require additional equity capital. Additionally, we may downgrade our portfolio companies if they are not meeting our financing criteria or are underperforming relative to their respective business plans. Various companies in our portfolio will require additional funding in the near term or have not met their business plans and therefore have been downgraded until their funding is complete or their operations improve. The slight increase in weighted average investment grading at December 31, 2018 from December 31, 2017 is primarily due to an overall decrease in positions with a credit rating of 1. At December 31, 2018, we had two debt investments onnon-accrual with a cumulative investment cost of approximately $2.7 million and zero fair value. At December 31, 2017, we had five debt investments on non-accrual with a cumulative investment cost and fair value of approximately $14.8 million and $340,000, respectively. The decrease in the cumulative cost and fair value of debt investments on non-accrual between December 31, 2018 and December 31, 2017 is the result of the liquidation of two debt investments that were on non-accrual at December 31, 2017, which resulted in a realized loss of approximately $10.3 million, slightly offset by a loan repayment in full from one debt investment.

Portfolio Composition. Our portfolio companies are primarily privately held companies and and, to a lesser extent, public companies which are active in the drug discovery and development, energy technology, internet consumer and business services, medical device and equipmentclean technology, software, drug delivery, specialty pharmaceuticals, communications medical device and networkingequipment, media/content/info, healthcare servicescommunications and networking, information services, surgical deviceshealthcare services, semiconductorsdiagnostic, specialty pharmaceuticals, biotechnology tools, surgical devices, consumer and business products, diagnostic and semiconductors, electronics and computer hardware and therapeutic industry sectors. These sectors are characterized by high margins, high growth rates, consolidation and product and market extension opportunities. Value for companies in these sectors is often vested in intangible assets and intellectual property. As of March 31June 30, 20142013, approximately 64.959.9% of the fair value of our portfolio was composed of investments in four industries: 23.220.8% was composed of investments in the drug discovery and development industry, 18.7% was composed of investments in the energy technology industry, 11.914.5% was composed of investments in the internet consumer and business services industry, 15.1% was composed of investments in the clean technology industry and 11.19.5% was composed of investments in the medical device and equipment industry. The following table shows the fair value of our portfolio by industry sector at March 31June 30, 2014 2013 (unaudited) and December 31, 20132012: March 31June 30, 2014 2013 December 31, 2013 2012 (in thousands) Investments at Fair Value Percentage of Total Portfolio Investments at Fair Value Percentage of Total Portfolio Drug Discovery & Development $ 206,535 23.2216,633 20.8% $ 219,169 24.1188,479 20.8% Energy Technology 166,482 18.7Clean Tech 158,611 15.1% 164,466 18.1126,600 14.0% Internet Consumer & Business Services 105,964 11.9150,592 14.5% 122,073 13.4136,149 15.0% Medical Devices Device & Equipment 99,061 11.199,014 9.5% 103,614 11.454,575 6.0% Software 79,077 8.988,954 8.5% 65,218 7.270,838 7.8% Drug Delivery 63,335 7.161,039 5.9% 62,022 6.874,218 8.2% Specialty Pharmaceuticals 40,217 4.5Information Services 49,894 4.8% 20,055 2.253,523 5.9% Communications & Networking 35,526 4.047,689 4.6% 35,979 37,560 4.1% Healthcare Services, Other 47,593 4.6% 36,481 4.0% Media/Content/Info 29,447 3.327,002 2.6% 8,679 1.051,534 5.7% Healthcare Services, Other 20,626 2.3Electronics & Computer Hardware 25,114 2.4% 29,080 3.212,715 1.4% Information Services 15,102 1.7Specialty Pharma 22,844 2.2% 46,565 5.112,473 1.4% Surgical Devices 10,353 1.112,010 1.2% 10,307 1.0% Semiconductors 9,464 1.1% 4,685 0.5% Biotechnology Tools 4,541 0.5% 5,275 0.611,358 1.3% Consumer & Business Products 3,282 0.410,606 1.0% 2,995 13,723 1.5% Diagnostic 10,543 1.0% 16,307 1.8% Semiconductors 6,880 0.7% 2,922 0.3% Diagnostic 858 0.1Biotechnology Tools 6,102 0.6% 902 0.1% Electronics & Computer Hardware 792 0.1% 9,211 1.06,845 0.8% $ 890,662 1,041,120 100.0% $ 910,295 906,300 100.0% Industry and sector concentrations vary as new loans are recorded and loans pay off. Loan revenue, consisting of interest, fees, and recognition of gains on equity and equity- related interests, can fluctuate materially dramatically when a loan is paid off or a related warrant or equity interest is sold. Revenue recognition in any given year can be highly concentrated among several portfolio companies. For the threesix-months ended March 31June 30, 2014 2013 and the year ended December 31, 20132012, our ten largest portfolio companies represented approximately 29.530.6% and 29.335.2% of the total fair value of our investments in portfolio companies, respectively. At both March 31June 30, 2014 2013 and December 31, 20132012, we had one investment four and eight investments, respectively, that represented 5% or more of our net assets. At March 31June 30, 20142013, we had five seven equity investments representing approximately 71.067.9% of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity investments. At December 31, 20132012, we had six equity investments which represented approximately 75.770.9% of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity such investments. As of March 31June 30, 20142013, 100over 98.8% of our debt investments were in a senior secured first lien position, and approximately 98.0more than 98.1% of the debt investment portfolio was priced at floating interest rates or floating interest rates with a Prime-Prime or LIBOR-LIBOR based interest rate floor. As a result, we believe we are well positioned to benefit should market interest rates increase. Our investments in senior secured debt with warrants have equity enhancement features, typically in the form of warrants or other equity-related securities designed to provide us with an opportunity for capital appreciation. Our warrant coverage generally ranges from 3% to 20% of the principal amount invested in a portfolio company, with a strike price generally equal to the most recent equity financing round. As of March 31June 30, 20142013, we held warrants in 107 120 portfolio companies, with a fair value of approximately $23.6 35.2 million. The fair value of our the warrant portfolio decreased has increased by approximately 33.7%, 19.3% as compared to a the fair value of $35.6 29.5 million at December 31, 2013 primarily related to the reversal of unrealized appreciation related to the exercise of our warrant positions in Neuralstem, Inc. ($751,000) and Box, Inc. ($8.3 million) to preferred stock2012. Our existing These warrant holdings currently would require us to invest approximately $68.6 74.8 million to exercise such warrants as of March 31, 2014warrants. Warrants may appreciate or depreciate in value depending largely upon the underlying portfolio company’s performance and overall market conditions. Of the warrants which we have monetized since inception, we have realized warrant gain multiples in the range of approximately 1.01x 1.04x to 14.91x based on the historical rate of return on our investments. However, our these warrants may not appreciate in value and, in fact, may decline in value. Accordingly, we may not be able to realize gains from our warrant portfoliointerests.

Portfolio Composition. Our portfolio companies are primarily privately held companies and public companies which are active in the drug discovery and & development, energy technologysoftware, internet consumer and & business services, medical device and equipment, software, drug delivery, specialty pharmaceuticals, communications and networking, media/content/info, sustainable and renewable technology, medical devices & equipment, drug delivery, healthcare services, specialty pharmaceuticals, information services, consumer & business products, surgical devices, semiconductors, electronics & computer hardware, communications & networking, biotechnology tools, consumer tools and business products, diagnostic and electronics and computer hardware industry sectors. These sectors are characterized by high margins, high growth rates, consolidation and product and market extension opportunities. Value for companies in these sectors is often vested in intangible assets and intellectual property. As of March December 31, 20142017, approximately 64.974.9% of the fair value of our portfolio was composed of investments in four five industries: 23.223.9% was composed of investments in the drug discovery and development industry, 18.723.4% was composed of investments in the energy technology software industry, 11.910.0% was composed of investments in the internet consumer and business services industry and 11.1industry, 9.9% was composed of investments in the medical device media/content/info industry and equipment 7.7% was composed of investments in the sustainable and renewable technology industry. The following table shows the fair value of our portfolio by industry sector at March December 31, 2014 (unaudited) 2017 and December 31, 20132016: March 31, 2014 December 31, 2013 2017 December 31, 2016 (in thousands) Investments at Fair Value Percentage of Total Portfolio Investments at Fair Value Percentage of Total Portfolio Drug Discovery & Development $ 206,535 23.2369,173 23.9% $ 219,169 24.1422,550 29.7% Energy Technology 166,482 18.7Software 360,123 23.4% 164,466 18.1219,559 15.4% Internet Consumer & Business Services 105,964 11.9154,909 10.0% 122,073 13.4% Medical Devices & Equipment 99,061 11.1% 103,614 11.4% Software 79,077 8.9% 65,218 7.2% Drug Delivery 63,335 7.1% 62,022 97,047 6.8% Specialty Pharmaceuticals 40,217 4.5% 20,055 2.2% Communications & Networking 35,526 4.0% 35,979 4.0% Media/Content/Info 29,447 3.3152,998 9.9% 8,679 1.0137,567 9.7% Sustainable and Renewable Technology 118,432 7.7% 154,406 10.9% Medical Devices & Equipment 94,595 6.1% 107,695 7.6% Drug Delivery 91,214 5.9% 109,834 7.7% Healthcare Services, Other 20,626 2.372,337 4.7% 29,080 3.230,200 2.1% Specialty Pharmaceuticals 37,501 2.4% 38,944 2.7% Information Services 15,102 1.724,618 1.6% 46,565 5.1% Surgical Devices 10,353 1.1% 10,307 1.0% Semiconductors 9,464 1.1% 4,685 0.5% Biotechnology Tools 4,541 0.5% 5,275 0.66,091 0.4% Consumer & Business Products 3,282 0.419,792 1.3% 2,995 0.342,713 3.0% Diagnostic 858 0.1S-75 December 31, 2017 December 31, 2016 (in thousands) Investments at Fair Value Percentage of Total Portfolio Investments at Fair Value Percentage of Total Portfolio Surgical Devices 13,161 0.9% 902 0.112,553 0.9% Semiconductors 10,406 0.7% 11,326 0.8% Electronics & Computer Hardware 792 9,982 0.6% 7,664 0.5% Communications & Networking 6,649 0.4% 18,019 1.3% Biotechnology Tools 5,604 0.4% 7,200 0.5% Diagnostic 720 0.1% 9,211 1.0574 0.0% Total $ 890,662 1,542,214 100.0% $ 910,295 1,423,942 100.0% Industry and sector concentrations vary as new loans are recorded and loans pay off. Loan revenue, consisting of interest, fees, and recognition of gains on equity and equity- warrants or other equity-related interests, can fluctuate materially when a loan is paid off or a related warrant or equity interest is sold. Revenue recognition in any given year can be highly concentrated among in several portfolio companies. For the three-months ended March 31, 2014 and the year years ended December 31, 20132017 and 2016, our ten largest portfolio companies represented approximately 29.534.6% and 29.334.0% of the total fair value of our investments in portfolio companies, respectively. At both March December 31, 2014 2017 and December 31, 20132016, we had one investment seven investments that represented 5% or more of our net assets. At March December 31, 20142017 and December 31, 2016, we had five nine and seven equity investments representing approximately 71.067.1% and 54.7%, respectively, of the total fair value of our equity investments, and each represented 5% or more of the total fair value of our equity investments. At December 31, 2013, we had six equity investments which represented approximately 75.7No single portfolio investment represents more than 10% of the total fair value of our equity investmentstotal investments as of December 31, 2017 and each represented 5% or more of the total fair value of our equity investments2016. As of March December 31, 20142017, 100% of our debt investments were in a senior secured first lien position, and approximately 98.096.4% of the debt investment portfolio was priced at floating interest rates or floating interest rates with a Prime-Prime or LIBOR-LIBOR- based interest rate floor. As a result, we believe we are well positioned to benefit should market interest rates increasecontinue to rise. As of December 31, 2017, 79.9% of our debt investments were in a senior secured first lien position, 19.8% were secured by a senior second priority security interest in all of the portfolio company’s assets, other than intellectual property, and the remaining 0.3% were unsecured as a result of the terms of the acquisition of one of our portfolio companies during the period. In the majority of cases, we collateralize our investments by obtaining a first priority security interest in a portfolio company’s assets, which may include its intellectual property. In other cases, we may obtain a negative pledge covering a company’s intellectual property. At December 31, 2017, of the approximately 79.9% of our debt investments in a senior secured first lien position, 45.1% were secured by a first priority security in all of the assets of the portfolio company, including its intellectual property and 34.8% were secured by a first priority security in all of the assets of the portfolio company and the portfolio company was prohibited from pledging or encumbering its intellectual property, or subject to a negative pledge. At December 31, 2017, we had no equipment only liens on material investments in our portfolio companies. Our investments in senior secured debt with warrants have detachable equity enhancement features, typically in the form of warrants or other equity-related securities designed to provide us with an opportunity for capital appreciation. These features are treated as OID and are accreted into interest income over the term of the loan as a yield enhancement. Our warrant coverage generally ranges from 3% to 20% of the principal amount invested in a portfolio company, with a strike price generally equal to the most recent equity financing round. As of March December 31, 20142017, we held warrants in 107 137 portfolio companies, with a fair value of approximately $23.6 36.8 million. The fair value of our warrant portfolio decreased increased by approximately 33.7%$9.3 million, as compared to a fair value of $35.6 27.5 million at December 31, 2013 2016, primarily related to the reversal addition of unrealized appreciation related to warrants in 20 new and 8 existing portfolio companies during the exercise of our warrant positions in Neuralstem, Inc. ($751,000) and Box, Inc. ($8.3 million) to preferred stockyear. Our existing warrant holdings currently would require us to invest approximately $68.6 87.6 million to exercise such warrants as of March December 31, 20142017. Warrants may appreciate or depreciate in value depending largely upon the underlying portfolio company’s performance and overall market conditions. Of the warrants which that we have monetized since inception, we have realized warrant gain multiples in the range of approximately 1.01x 1.02x to 14.91x 29.06x based on the historical rate of return on our investments. However, our warrants may not appreciate in value and, in fact, may decline in value. Accordingly, we may not be able to realize gains experience losses from our warrant portfolio.