Lloyd Howell
Analyst · Credit Suisse
Thanks, Horacio, and good morning, everyone. Let me start by echoing Horacio's comments on the closeout of our investment thesis. Last quarter marked the end of a 3-year period with ADEPS growth of 96%, an increase that was primarily driven by strong organic revenue growth and sustained margin expansion. This performance resulted from investments related to Vision 2020 and our early positioning in core areas of rising demand for our clients. Booz Allen has proven its ability to outperform competitors even in some of the toughest macro environments. Moving forward, we will keep a sharp focus on positioning Booz Allen for long-term success, building on the excellent performance of the last 3 years.
As we look back over the past year, we are proud of the resilience and dedication shown by our people in close collaboration with our clients. Their excellent work resulted in another strong year of operational and financial performance. As we begin fiscal year 2022 and anticipate moving toward a post-pandemic operating rhythm, we expect some choppiness, but we have clear operational focus areas. Our confidence in our continued success is grounded in our record of consistent performance and the strong foundation we have built to deliver on near- and long-term objectives.
Let's turn to our fiscal year 2021 results. Please turn to Slide 6. At the top line, revenue increased 5.3% for the full year to $7.9 billion. Revenue, excluding billable expenses, grew 7.1% to $5.5 billion. This organic top line growth largely reflects strong execution on sustained demand for our services, helped by higher-than-normal staff utilization in the first half of the year.
As a reminder, in January, we adjusted our revenue guidance to a range of 4.8% to 6% due to 3 factors: first, programmatic shift in the presidential transition period; second, a snapback to more typical PTO usage; and third, lower expectations for billable expenses as a percentage of revenue, which landed in the low end of our 29% to 31% range. These factors played out in the fourth quarter as expected.
Let me step through the market performance. Revenue growth for the full year was led by our defense and civil businesses, which grew 9% and 8%, respectively. In defense, growth slowed in the second half of the year due to the factors I noted earlier. However, underlying long-term demand for our services and solutions remain strong as evidenced by recent business wins and continued tactical sales execution.
Growth in our civil business also slowed in the second half of the year. This was largely related to a pause on a large cyber program due to funding availability, which occurred in the third quarter and continued into the fourth quarter. Given the importance and criticality of this program for the client, we believe work will ramp up again in the coming quarters.
Revenue from our intelligence business declined 3% for the full year. Our focused effort to reshape that portfolio continues, and we are pleased with the results so far. We expect to see our intelligence business return to growth in this fiscal year as we ramp up recent contract wins. Furthermore, the pandemic-related headwind we faced in fiscal year 2021 and inability to bill for fee will continue to abate as more and more of our employees return to work at client facilities.
Lastly, revenue in global commercial, which accounted for approximately 3% of our total revenue in fiscal year 2021, declined 22% year-over-year. The drop was primarily driven by our decision to exit from parts of our Middle East business due to market dynamics and geopolitical trends and to focus strategically on our U.S.-based cyber business.
Please turn to Slide 7. We are pleased with our excellent book-to-bill performance for the quarter and the full year. Book-to-bill of 1.38x was a fourth quarter record, resulting in a full year book-to-bill of 1.42x. Total backlog grew 16%, yielding our largest ever fiscal year-end backlog of $24 billion. Funded backlog grew 3% to $3.5 billion. Unfunded backlog grew 35% to $6.1 billion. And price options grew 13% to $14.4 billion.
Throughout the year, the team did a great job sustaining our historical win rates for recompetes and new work even as we navigated the pandemic and a presidential transition period. As we've noted previously, we continue to augment our traditional foundation of diversified, smaller awards by pursuing larger and more complex bids that, by their very nature, cause quarter-to-quarter volatility in book-to-bill. Our record backlog speaks to ongoing robust demand for our services, the quality of our people and our closeness to clients' missions.
Pivoting to headcount. As of March 31, we had 27,727 employees, up by 554 year-over-year or 2%. Excluding the impact of our contract divestiture in the third quarter, headcount would have been up 2.4%. As Horacio emphasized, we are focused on accelerating headcount growth to meet strong demand signals and execute our backlog.
Moving to the bottom line. Adjusted EBITDA for fiscal year 2021 was $840 million, up 11.4% from the previous year. This increase was driven primarily by our top line growth, strong cost management and lower-than-expected billable expense mix in what was truly an anomalous year. As a result, our adjusted EBITDA margin for the full year was 10.7%.
Full year net income, diluted EPS and ADEPS also grew significantly. Net income increased 26% year-over-year to $609 million. Adjusted net income was $542 million, up 21% from the previous year. Diluted earnings per share increased 28% to $4.37 from $3.41 the year prior. And adjusted diluted earnings per share increased 23% to $3.90 from $3.18 the year prior. These increases were primarily driven by strong operating performance, a lower effective tax rate and a lower share count in fiscal year 2021 due to our share repurchase program.
Regarding our effective tax rate, during the fourth quarter, we recognized a tax benefit under the CARES Act that allowed tax loss carrybacks to prior tax years. As a result, we recognized approximately $77 million in remeasurement tax benefit this quarter, which we excluded from adjusted net income and adjusted diluted earnings per share.
Turning to cash. We put a plan in place 3 years ago to improve cash generation. We are extremely proud of our team's performance this year, which we see as the culmination of this multiyear effort. We generated $719 million in operating cash during fiscal year 2021, representing 30% growth over the previous year. That put us above the top end of our forecasted range, and we ended the year with $991 million of cash on hand.
Strong cash performance was largely driven by collections growth in excess of revenue growth. Higher cash taxes on the year were offset by relatively light disbursements related to operating in the COVID-19 environment. Capital expenditures for the year totaled $87 million, in line with our expectations as we continue to invest in infrastructure and technology to support virtual work.
April was a key month for us as we went live with our new next-gen financial system. Our year-end reporting close went smoothly, and we have not encountered any material issues to date. As can be expected, we experienced a few minor issues, which were addressed promptly. We have already been reaping the benefits in the form of increased data access and improved productivity. We expect this to translate into cost savings over time, which will be reinvested to help drive future growth.
I want to thank all of my colleagues who worked tirelessly to make this a seamless and successful transition. I will touch on this topic again in our outlook for fiscal year 2022.
Please turn to Slide 8. In fiscal year 2021, we continued to execute on a prudent capital allocation strategy designed to deliver both near- and long-term shareholder value. We returned approximately $181 million to shareholders through quarterly dividends, which included a 19% year-over-year dividend increase in the fourth quarter. This was the eighth consecutive fiscal year of double-digit growth in our quarterly dividend.
We also repurchased 4.1 million shares for $318 million during the fiscal year with 2.3 million shares repurchased for $185 million in the fourth quarter. In combination with our third quarter investment in Tracepoint, we deployed a total of $571 million in capital in fiscal year 2021.
Going forward, our capital allocation priorities remain unchanged: reinvesting in our business; securing our quarterly dividend; strategic acquisitions; and share repurchases. Today, we are also announcing that our Board has approved a regular dividend of $0.37 per share payable on June 30 to stockholders of record on June 15. Dividends remain an important component of our strategy to create value for shareholders.
Lastly, I want to briefly touch on our recently announced acquisition of Liberty IT Solutions. This transaction, upon close, will be our largest acquisition to date and will be immediately accretive to revenue growth, adjusted EBITDA margin and adjusted diluted earnings per share. For us, this transaction represents exactly what we look for in acquisitions: cultural, strategic and financial fit.
As we look ahead, we are focused on 3 objectives: first, a smooth and successful integration; second, continued hiring to help scale up Liberty's recent wins; and third, maintaining excellence in contract delivery. As Horacio noted, we are excited about the acquisition and the long-term value it will create for our shareholders and the people of both Booz Allen and Liberty. We look forward to sharing updates in the months to come.
Turning to guidance. Please move to Slide 9. Fiscal year 2021 was certainly a year of unprecedented challenges for our people and clients. This resulted in several puts and takes to our fiscal year 2021 financial results, which influence year-over-year comparisons as we move into fiscal year 2022. Most of these factors are temporary in nature. However, we expect them to constrain top line growth for the next couple of quarters before an acceleration into the back half of the fiscal year.
Let me step through these factors. First, there is a natural ramp-up that needs to occur in both execution of work on recently won contracts and on recruiting and hiring. As Horacio noted, we are focused on both of those priorities. They take time to ramp up, which creates a momentum built towards the back half of the year.
Second, we saw unusually high productivity in the first half of fiscal year 2021, driving up revenue growth then slowing growth in the second half as staff utilization and PTO trends normalize. This dynamic will create challenging comps in the first half of fiscal year 2022.
Third, we expect PTO trends to have an ongoing impact for the next few months. Although we executed a successful onetime PTO buyback program in the fourth quarter, we know that many of our employees still have elevated balances due to the pandemic. With vaccinations increasing and some are on the way, we expect and have been encouraging our people to take well-deserved time off.
Lastly, our implementation of the new financial system will result in minor timing differences in the costing of labor. We do not expect this dynamic to materially impact our full year results. However, we do forecast approximately 50 basis points of revenue growth headwinds in each of our second and third quarters, recovered through a roughly 100 basis point tailwind in the fourth quarter.
Putting it all together, we expect organic top line growth in the low single-digit range in the first half of fiscal year 2022 with a significant ramp into the third and fourth quarters. From an EBITDA perspective, a return to more normal indirect spending patterns and billable expense mix post-pandemic will drive some volatility in our quarterly margin profile.
Now let me take you through our fiscal year 2022 guidance. We expect total revenue to grow between 7% and 10%, which is inclusive of a partial year contribution from our announced Liberty acquisition, assuming a first quarter 2022 close. The variance between the top and bottom end of our revenue growth outlook will largely depend on the successful execution and timing of our hiring and onboarding.
We expect adjusted EBITDA margin to remain in the mid-10% range. We expect adjusted diluted earnings per share to be between $4.10 and $4.30. This range reflects strong organic growth, incremental D&A expense related to our new financial system, a higher effective tax rate and $0.20 to $0.24 of anticipated accretion from our acquisition of Liberty IT. This guidance is based on 134 million to 137 million weighted average shares outstanding and a tax rate in the range of 22% to 24%.
We expect operating cash flow to be between $800 million and $850 million, largely driven by our operational performance, lower cash tax payments and contributions from Liberty IT. And finally, we expect CapEx to be between $80 million and $100 million as we continue to invest in infrastructure and technology.
In closing, we are extremely proud of our fiscal year 2021 performance. I want to thank our clients and the entire Booz Allen family for managing through a complex year. We have once again demonstrated our ability to effectively manage the business, invest in our people and deliver strong returns to our shareholders. We did all of this while weathering a tough macro environment, which gives us confidence in our strategy and positioning to succeed through any market condition.
With that, Rubun, let's open the lines for questions.