For the full year 2020, GTS contract value grew 4%.
Client engagement continue to be strong with both content and analyst interactions up 30% versus 2019.
GBS contract value continued to perform well throughout the year with contract value growth of 7%.
New business growth was a very strong 26% in the quarter, driven by our GxL product line.
Our consulting segment was also impacted by the pandemic with revenues down 12% in Q4 and 5% for the full year 2020.
For example, we've signed contracts for our Stamford headquarters and our U.K. hub to be powered by 100% renewable energy.
Our board authorized an additional $300 million for repurchases, bringing the total available to around $860 million.
Reviewing our year-over-year financial performance, for the full year 2020, total contract value increased 4%, total FX-neutral revenue was down 3%, FX-neutral adjusted EBITDA increased 20%, diluted adjusted earnings per share was a strong $4.89 and free cash flow was $819 million, up almost 100% from 2019.
Fourth quarter revenue was $1.1 billion, down 8% as reported and 9% FX-neutral.
Excluding conferences, our revenues were up 2% year-over-year FX-neutral.
In addition, total contribution margin was 68%, up more than 580 basis points versus the prior year.
EBITDA was $245 million, up 13% year-over-year and up 10% FX-neutral.
Adjusted earnings per share was $1.59, and free cash flow in the quarter was a robust $237 million.
Research revenue in the fourth quarter grew 5% year-over-year as reported and 4% on an FX-neutral basis.
Fourth quarter research contribution margin was 72%, benefiting in part from the temporary cost avoidance initiatives we put in place starting in the first quarter of 2020.
Total contract value grew 4% FX-neutral to $3.6 billion at December 31.
For the full year 2020, research revenues increased by 7%, both on a reported and FX-neutral basis.
The gross contribution margin was 72%, up about 240 basis points from the prior year.
Global Technology Sales contract value at the end of the fourth quarter was $2.9 billion, up almost 4% versus the prior year.
While retention for GTS was 98% for the quarter, down about 600 basis points year-over-year, a majority of our industry groups saw retention improve from the third quarter.
GTS new business declined 5% versus last year, an improvement from both the second and third quarters.
Global Business Sales contract value was $696 million at the end of the fourth quarter.
That's about 20% of our total contract value.
CV increased 7% year-over-year.
All practices contributed to the 7% CV growth rate for GBS with the exception of marketing, which was impacted by discontinued products.
Wallet retention for GBS was 101% for the quarter, down 43 basis points year-over-year.
GBS new business was up 26% over last year, led by very strong growth in HR, finance and legal.
We held 13 virtual conferences in the fourth quarter.
Conferences revenue for the quarter was $93 million.
Contribution margin in the quarter was 78%.
For the full year 2020, revenue decreased by 75%, both on a reported and FX-neutral basis.
Gross contribution margin was 48%, down about 290 basis points from 2019 as we maintained some of our cost of service as well as SG&A despite the lower revenue.
Fourth quarter consulting revenues decreased by 10% year-over-year to $94 million.
On an FX-neutral basis, revenues declined 12%.
Consulting contribution margin was 26% in the fourth quarter, down about 160 basis points versus the prior year quarter due to lower contract optimization revenue, which usually flows through at high margins.
Labor-based revenues were $73 million, down 10% versus Q4 of last year or 12% on an FX-neutral basis.
Labor-based billable headcount of 730 was down 10%.
Utilization was 63%, up about 300 basis points year-over-year.
Backlog at December 31 was $100 million, down 14% year-over-year on an FX-neutral basis.
Our contract optimization business was down 9% on a reported basis versus the prior year quarter.
Full year consulting revenue was down 4% on a reported basis and 5% on an FX-neutral basis and its gross contribution margin of 31% was up 68 basis points from 2019.
SG&A decreased 6% year-over-year in the fourth quarter.
For the full year, SG&A decreased 3% on a reported and FX-neutral basis.
EBITDA for the fourth quarter was $245 million, up 13% year-over-year on a reported basis and up 10% FX-neutral.
Depreciation in the quarter was up approximately $4.5 million from last year, including expense acceleration from facilities-related charges.
Amortization was down about $800,000 sequentially.
Net interest expense, excluding deferred financing costs in the quarter was $26 million, flat versus the fourth quarter of 2019.
The Q4 adjusted tax rate, which we use for the calculation of adjusted net income, was 25% for the quarter.
The tax rate for the items used to adjusted net income was 28.4% in the quarter.
The adjusted tax rate for the full year was 21%.
Adjusted earnings per share in Q4 was $1.59.
For the full year, adjusted earnings per share was $4.89.
EPS growth for the year was 25%.
Note that about $7 million of equity compensation expense, which we normally would have incurred in the fourth quarter, has shifted into the first quarter of 2021.
That was a benefit to fourth quarter adjusted earnings per share of about $0.07.
Operating cash flow for the quarter was $260 million compared to $83 million last year.
Capex for the quarter was $23 million, down 57% year-over-year.
Free cash flow for the quarter was $237 million, which is up about 700% versus prior year.
Free cash flow as a percent of revenue or free cash flow margin was 20% on a rolling four quarter basis, continuing the improvement we have been making over the past few years.
Adjusted for timing and one-time benefits, 2020 normalized free cash flow margin is around 13%.
Our December 31 debt balance was $2 billion.
At the end of the fourth quarter, we had about $1 billion of revolver capacity.
Our reported gross debt to trailing 12 month EBITDA is about 2.5 times.
At the end of the fourth quarter, we had $713 million of cash.
We resumed our share repurchases after pausing earlier in the year, buying back $100 million in stock at an average price of $156 per share.
The board recently increased our share repurchase authorization by $300 million because we have significant capacity for buybacks from cash on hand and expected free cash flow.
As of February 8, we have around $860 million available for open-market repurchases.
We expect research revenue of at least $3.815 billion, which is growth of at least 5.9%.
We expect conferences revenue of at least $160 million, which is growth of at least 33%.
We expect consulting revenue of at least $390 million, which is growth of at least 3.6%.
The result is an outlook for consolidated revenue of at least $4.365 billion, which is growth of 6.5%.
Based on current foreign exchange rates and business mix, the consolidated growth includes an FX benefit of about 200 basis points.
We expect full year adjusted EBITDA of at least $760 million, which is a decline of about 7% and reported margins of at least 17.4%.
We expect our full year 2021 adjusted net interest expense to be $102 million.
We expect an adjusted tax rate of around 22% for 2021.
We expect 2021 adjusted earnings per share of at least $4.10.
For 2021, we expect free cash flow of at least $630 million.
Our 2020 ending contract value at 2021 FX rates is $2.9 billion for GTS and $706 million for GBS.
Finally, we expect to deliver at least $200 million of EBITDA in Q1 of 2021.

Summary:
Fourth quarter revenue was $1.1 billion, down 8% as reported and 9% FX-neutral.
Adjusted earnings per share was $1.59, and free cash flow in the quarter was a robust $237 million.
Adjusted earnings per share in Q4 was $1.59.