Mathew Pendo
Analyst · Hovde Group
Thanks, Mike, and thank you to everyone for joining this call. The fourth quarter completed a strong fiscal year for OCSL. We generated solid financial results and investment performance that was highlighted by robust origination activity and pristine credit quality. We, again, grew NAV and meaningfully increased our dividend.
Full year 2021 adjusted net investment income per share was $0.64, up from $0.51 for fiscal 2020, driven by higher adjusted investment income reflecting our larger investment portfolio as well as higher prepayment fees and OID acceleration on some of our investments made in the wake of the pandemic. Importantly, this marked our highest annual level of adjusted net investment income under Oaktree's management, and represents the tremendous progress we have made since taking over management of the company 4 years ago, as well as the realization of synergies from the merger with OCSI, which closed earlier this year.
Given the strength and consistency of our earnings, our Board increased our quarterly dividend by 7% to $0.155 per share. This was the sixth consecutive quarterly increase and represented a 41% increase from a year earlier. Our dividend is now up 63% from its pre-COVID level. We reported NAV per share of $7.28, up 1% from the prior quarter, and up 12% for the full year. The quarterly increase reflected the continued price appreciation on certain debt and equity investments, and for the annual increase, successful realizations contributed as well. Importantly, our NAV continued to exceed its pre-COVID high and was up more than 10% from the end of calendar 2019.
We had another strong year of originations. During full year 2021, we leveraged Oaktree's credit platform to generate nearly $1.2 billion of new investment commitments. Many of our new originations have been in the form of directly originated investments where we co-invested alongside other Oaktree funds. These new originations, in aggregate, were attractively priced at approximately 8.6%, which exceeded the yield on investments that were exited the year by approximately 2%. This ongoing shift in the portfolio towards higher-yielding proprietary investments has led to improved debt portfolio yield, which increased to 8.7% at year-end from 8.3% 1 year ago. Importantly, this all occurred against the backdrop of LIBOR remaining at all-time lows throughout the fiscal year.
Credit quality remains very strong. It's a testament to our disciplined underwriting and risk controlled approach to investing. As with the prior quarter, we had no investments on nonaccrual at the close of the fourth quarter, and noncore investments represented just 5% of their portfolio at fair value at quarter end. And to start fiscal year-end, I also wanted to iterate some of the key improvements we have made to our capital structure since the closing of the merger with OCSI in March. These changes enhance our flexibility and meaningfully lowered our cost of debt capital. In May, we issued $350 million of senior notes at a 2.7% coupon, which we subsequently swapped to a floating rate at LIBOR plus 1.66% to better match the floating rate nature of our underlying investment portfolio. We also amended our syndicated credit facility, increasing the size to $950 million from $800 million and extending maturity by 2 years to May 2026. Additionally, we retired a higher-cost credit facility acquired from OCSI, and we amended the City facility to reduce costs in some of our lower-yielding quoted loans. By taking these steps, we proactively reduced our weighted average interest rate on debt outstanding to 2.4%, down 30 basis points from 2.7% in last year's fourth quarter.
We also improved our funding profile by more than doubling our unsecured borrowings outstanding, and boosted our borrowing capacity by more than $300 million. Finally, we received a strong vote of support from our investment advisor, Oaktree, who purchased 2.3% of outstanding shares from our largest shareholder in September. Oaktree, along with our management team and directors, now own 3.1% of OCSL shares, which we believe further strengthens the alignment between us and our advisors.
Before turning the call over to Armen, I wanted to remind you that Mel has announced he will step down as CFO and Treasurer of OCSL at the end of November to assume another senior management role within Oaktree. We thank Mel for his financial stewardship over the last 4 years, and of course, wish him well in the new position. Chris McKown, a Managing Director of Oaktree, will become OCSL's CFO and Treasurer, effective upon Mel's resignation. Chris currently serves as OCSL's assistant treasurer, has worked closely with Mel since we took over management of the company in 2017. Chris is very well suited and prepared to step into his new role, and he will do so at a time when we are exceptionally well positioned for fiscal 2022.
Now I would like to turn the call over to Armen.