While they were necessary, we are pleased to share that as planned, marketing and admissions teams have begun to revert to normalized levels of operations in the fourth quarter and commensurately as compared to the fourth quarter, we expect AIU System to experience significant total enrollment growth in subsequent quarters. Third quarter revenue at CTU was $120.6 million or 23.6% higher than the prior year quarter, primarily due to a positive timing impact from the academic calendar redesign and the 2022 acquisition as well as growth in our underlying organic enrollments. Operating income for the quarter increased to $34.5 million as compared to $31.5 million as revenue growth was partially offset with increased expenses in academics and other student support areas as well as for our recent acquisitions.
Turning to AIU System. Revenue decreased 16.1% to $59.2 million for the quarter, driven by the decrease in total student enrollments. Operating income for the quarter increased to $15.6 million as compared to $9.6 million as lower operating expenses primarily within admissions and marketing, more than offset the decrease in revenue. Overall, we ended the quarter on a high note as it relates to student retention engagement at both our academic institutions, partly aided by the positive impact from Federal Student Aid initiatives. Moving on to corporate and other. Third quarter operating loss was $7 million as compared to an operating loss of $11.8 million in the prior year quarter. Legal fees primarily associated with responses to the Department of Education relating to loan forgiveness applications by former students were lower for the current quarter.
Please refer to the disclosures regarding borrower defense to repayment in our 10-K that was filed earlier this year for additional information on this matter. Now to income taxes. For the third quarter, we recorded a provision for income taxes of $6.8 million resulting in an effective tax rate of 14.1%. The effective tax rate for the current quarter was impacted by a $4.5 million favorable discrete adjustment related to the recognition of the tax benefits associated with the previously disclosed prior year ordinary loss attributable to a subsidiary, which decreased the effective tax rate for the quarter by 9.3%. Additionally, the current quarter effective tax rate reflects the impact of provision to return tax credit adjustments, the tax effect of stock compensation, and the release of other previously recorded tax reserves, the combination of which reduced the effective tax rate by 0.8%.
Finally, we expect that for the full year 2023, our effective tax rate will be between 22.5% and 23.5%. Moving to the balance sheet. For the third quarter, net cash flow from operations was $32.6 million versus $52.9 million in the prior year quarter, while year-to-date cash flow was $98.8 million versus $107.6 million. We ended the quarter with $603.7 million of cash, cash equivalents, restricted cash and available-for-sale short-term investments, which was approximately $85.5 million higher versus year-end 2022. Capital expenditures for the third quarter were approximately $1.2 million or 0.7% of revenue. For full year 2023, we foresee capital expenditures to be approximately 1% of revenues. Before I share the updated outlook, let me take a minute on capital allocation.
During last quarter’s call, we announced our inaugural quarterly dividend that was paid in September 2023. Today, we are pleased to announce that consistent with our dividend policy, the Board of Directors have approved the third quarter 2023 dividend payment of $0.11 per share, payable on December 15, 2023, to the holders of record of Perdoceo’s common stock at the close of business on December 1, 2023. To provide context, on an annualized basis, this quarterly dividend represents roughly 20% of our trailing 12-month free cash flows. Future quarterly dividends are expected to be paid out of the free cash flow for the relevant year, subject to Board approval and the company’s available retained earnings, financial condition and other relevant factors.
Subject to the requirements just mentioned, we expect quarterly dividend payments will be an integral and growing part of our balanced capital allocation strategy, which also prioritizes investments in organic projects in particular, technology-related initiatives designed to benefit our students and maintaining a strong balance sheet. We will also continue to evaluate diverse strategies to enhance stockholder value including acquisitions and share repurchases. Turning to our updated outlook for 2023. We are again raising our full year adjusted operating income outlook to now range between $171 million and $174 million as compared to the previously provided range of $165 million to $172 million. Further, adjusted earnings per diluted share is expected to range between $2.03 and $2.06 versus $1.63 in 2022.
