We are pleased to report that we were able to monetize a meaningful amount of non-core assetsiv during the year, and as a result, non-core assets have declined to a nominal amount of the portfolio. Non-core assetsiv are higher on the risk spectrum and have more volatile results. We also intend to reduce our investment in Merx Aviation, our aircraft leasing portfolio company in the coming year by selling aircraft and de-emphasizing the aircraft servicing business. At the end of the year, Merx Aviation represented 12% of AINV’s total portfolio.
Our financial performance this past year was negatively impacted by the performance of certain non-core asserts. For the year, total investment income was $213.2 million, net investment income was $96.0 million, net investment income per share was $1.49, and GAAP earnings per share was $1.28. NAV per share was $15.79 at the end of the year. With the total return provision in our incentive fee calculation, which nets the impact of realized and unrealized gains and lossesvi incentive fees were below the stated fee rates. The Board of Directors declared a 31-cent base distribution and a 5-cent supplement distribution per share in each quarter during the year. Total distribution declared during the year were $1.44 per share. The total return to our stockholders for the year was 7.4%.vii
Throughout the year, AINV was focused on operating within its target leverage range. AINV’s net leverage ratio viii was 1.51x at the end of the year, in the middle of its target range. Gross fundings of $1.14 billion were mostly offset by $1.07 billion of sales and repayments. Net fundings for the year were $66 million. Likewise, new lending commitments were in large part offset by the exit of commitments. During the year, the Company made $941 million in new investment commitmentsix to 82 different borrowers. Consistent with our investment strategy, 100% of new debt commitments were first lien, 97% were floating rate and 94% were made pursuant to our co-investment order.x Also, during the year, the Company exited approximately $814 million of investment commitments including $132 million of second lien commitments. We ended the year with a $2.52 billion investment portfolio, at fair value, deployed across 139 borrowers in 26 different industries.
We ended the year with a solid balance sheet and strong liquidity. During the year, we focused on diversifying and extended the maturity profile of our funding sources. In July 2021, we took advantage of low interest rates and strong investor demand to issue $125 million of five-year unsecured debt. We believe that increasing the fixed rate unsecured portion of our liabilities enhances our financial flexibility and provides AINV with the potential for higher earnings if interest rates continue to rise. This debt issuance has proven to be particularly well-timed given that interest rates and credit spreads have increased markedly since issuance. We are also pleased that in July 2021, Kroll Bond Rating Agency affirmed our investment grade credit rating.
Longer-term we believe the direct lending market is poised for continued growth due to the strong growth in private equity capital targeting middle market companies. Middle market companies and their private equity sponsors are increasingly opting for private debt solutions over broadly syndicated loans. We believe AINV is well-positioned to benefit from this ongoing trend.
As we look ahead, we are confident that we have put AINV on the right path to generate stable and attractive returns for our shareholders. Our corporate lending portfolio is extremely well-positioned to weather potential economic weakness. We have an experienced leadership team that has managed through multiple economic cycles.
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