Regarding our Q4 performance, our revenues were $4.39 billion, approximately $85 million above the top end of our guidance.
Concerning adjusted EBIT margin, we delivered 7.5%, also higher than the top end of our guidance.
Book-to-bill for the quarter was 1.08, underscoring the success of bringing the new DXC, which focuses on our customers and colleagues to the market.
This is the fourth straight quarter that we've delivered a 1.0 or better book-to-bill.
We have achieved our goal of $550 million of cost savings in FY '21.
Our cost optimization program was responsible for the strong adjusted EBIT margin of 7.5% in Q4.
So the 1.08 book-to-bill that we delivered this quarter is consistent evidence that our plan is working.
In Q4, 53% of our bookings were new work and 47% were renewals.
Our ability to deliver a consistent book-to-bill of over 1.0 in each of the four quarters of FY '21 is clear evidence that we can win in the IT services industry.
We paid down $6.5 billion of debt in the past nine months and subsequent to year-end, retired an additional $500 million.
We are now approaching a far more manageable $5 billion debt level.
Fourth, we will reduce restructuring and TSI expense to approximately $550 million in FY '22 to under $100 million in FY '24, ultimately improving cash flow.
GAAP revenue was $4.39 billion, $85 million higher than the top end of our guidance.
On an organic basis, revenue increased 0.4% sequentially.
Organic revenue declined 7% year over year due to the previously disclosed runoffs and terminations.
As we mentioned on our third-quarter earnings call, our Q3 10.5% year-over-year decline would be the high watermark.
GAAP EBIT margins were negative 16.8% in the fourth quarter, impacted by approximately $1.1 billion of costs, including pension mark-to-market, asset impairments, restructuring TSI, loss on disposals, and debt extinguishment costs.
Excluding these items, adjusted EBIT margin was 7.5% in the fourth quarter, an improvement of 50 basis points from the third quarter.
Non-GAAP diluted earnings per share was $0.74 and was negatively impacted by $0.04 due to a higher-than-expected tax rate of 32%.
In Q4, bookings were $4.7 billion for a book-to-bill of 1.08, the fourth straight quarter of a book-to-bill greater than one.
For the full year, this takes our book-to-bill to 1.12, compared to 0.9 in FY '20.
GBS was $2 billion or 46% of our total Q4 revenue.
Organic revenues increased 2% sequentially, primarily reflecting the strength of our applications and analytics and engineering business.
Year over year, GBS revenue was down 4% on an organic basis.
GBS segment profit was $315 million with a 15.8% profit rate, up 160 basis points from Q3.
GBS bookings for the quarter were $2.39 billion for a book-to-bill of 1.2 and a full-year book-to-bill of 1.32, compared to 0.99 in the prior year.
Revenue was $2.39 billion, down 0.9% sequentially and down 9.3% year over year on an organic basis due to the previously disclosed terminations and runoffs.
The ITO business benefited from approximately $100 million of resale revenue, resulting from a typical Q4 increase of customer demand due to their fiscal year-end.
GIS segment profit was $98 million with a profit margin of 4.1%, a 40-basis-point margin improvement over the third quarter.
GIS bookings were $2.3 billion for a book-to-bill of 0.98.
Book-to-bill for FY '21 was 0.94, compared to 0.83 in the prior year.
IT outsourcing revenue was $1.19 billion in the quarter, up 1.4%, the first positive sequential growth since we began tracking in this manner.
ITO book-to-bill was 0.98 in the quarter.
Cloud and security revenue was $524 million, declined 1.6% sequentially, and was down 5.7% year over year.
The cloud and security business had a difficult compare as the third quarter grew 4.7% sequentially.
Book-to-bill was 1.08 in the quarter.
Moving up the stack, the applications layer posted a 1.9% sequential growth and was down 7.2% year over year.
Analytics and engineering revenues were $478 million, up 2% on a sequential basis and up 8.4% compared to prior year.
Analytics and engineering book-to-bill was 1.46 in the quarter.
The modern workplace and BPS revenues were $795 million, down 3.3% sequentially and down 10.5% compared to the prior year.
Fourth-quarter cash flow from operations totaled an outflow of $280 million.
Free cash flow for the year was negative $652 million, impacted primarily by four nonrecurring items.
Q4 tax payments of $531 million related to the business sale.
As you may recall, we planned $900 million of tax payments, so this result surpassed our expectation.
As we told you before, in Q3, $832 million related to readying the U.S. state and local Health and Human Services business for sale and normalizing payables and $200 million related to deferrals of certain tax payments due to COVID relief legislation that will be paid during FY '22.
Since DXC was formed four years ago, we had significant cash outflows with approximately $900 million in expense per year on average.
In FY '22, this will be reduced to approximately $550 million, with a larger portion being allocated to facilities restructuring efforts to improve the work experience for our people as we reshape our portfolio for our virtual model.
As you can see, we have achieved a lot in this area, reducing our net debt leverage ratio by more than one turn from the high watermark of 2.4 to one at the end of March.
Organic revenues declines are expected to moderate, down 2% to down 4% in the first quarter year over year.
This translates into reported revenues between $4.08 billion and $4.13 billion.
Our sequential revenue is lower for two reasons: first, previously mentioned lumpiness of resale revenue that occurs in Q4; second, our portfolio-shaping efforts reduced revenue by about $100 million.
EBIT margin 7.4% to 7.8% includes 20 basis points of margin headwinds due to the sale of our healthcare provider software business.
Non-GAAP diluted earnings per share in the range of $0.72 to $0.76.
Organic revenue growth of minus 1% to minus 2%.
On a year-over-year basis, divestitures will account for $1.2 billion of the revenue decline.
This translates into revenue of $16.6 billion to $16.8 billion; EBIT margin, 8.2% to 8.7%; non-GAAP diluted earnings per share of $3.45 to $3.65, an increase of 42% to 50% year over year; free cash flow of $500 million.
Organic revenue growth of 1% to 3%; adjusted EBIT margin of approximately 10% to 11%; non-GAAP diluted earnings per share of $5 to $5.25; free cash flow of approximately $1.5 billion.
In the market, we went from losing to winning, and we repaid over $6 billion in debt, taking our balance sheet from highly leveraged to strengthened.

Summary:
Non-GAAP diluted earnings per share was $0.74 and was negatively impacted by $0.04 due to a higher-than-expected tax rate of 32%.
This translates into reported revenues between $4.08 billion and $4.13 billion.
Non-GAAP diluted earnings per share in the range of $0.72 to $0.76.
This translates into revenue of $16.6 billion to $16.8 billion; EBIT margin, 8.2% to 8.7%; non-GAAP diluted earnings per share of $3.45 to $3.65, an increase of 42% to 50% year over year; free cash flow of $500 million.
Organic revenue growth of 1% to 3%; adjusted EBIT margin of approximately 10% to 11%; non-GAAP diluted earnings per share of $5 to $5.25; free cash flow of approximately $1.5 billion.