Our net organic revenue growth in the second quarter was 19.8%.
That's against the second quarter of 2020 when as you will recall our organic change was negative 9.9%, which while well ahead of our peer group did mark our steepest decrease of the recession.
It's also important to note that our 7.9% organic increase this quarter relative to the pre-pandemic second quarter of 2019.
In the US, it was 17.4%, growth in our international markets ranged from 14% in the Asia-Pacific region to 49% in Latin America.
Our IAN segment grew 20.5% organically with increases led by media, data and technology and with solid contributions from our global integrated networks.
At our DXTRA segment, organic growth was 15.1% with strong increases from last year's heavily impacted Q2 across Octagon's sports and entertainment and Jack Morton's experiential offerings.
The auto, retail and other sectors were up more than 20%, consumer goods, tech and telecom and healthcare increased in the mid to high teens, food and beverage and financial services were up in the low double-digit range.
Our second quarter net income was $263.3 million as reported.
Adjusted EBITDA was $405.8 million and adjusted EBITDA margin on net revenue was 17.9%.
Diluted earnings per share was $0.66 as reported and was $0.70 as adjusted for the after tax expense of the amortization of acquired intangibles.
At that time, we outlined our view toward full year organic growth of 5% to 6% and adjusted EBITDA margin of approximately 15.5%.
With predicated on the continued progress and public health issues, we believe that we can deliver organic growth for the full year of 9% to 10%.
And with that level of growth, we would expect to achieve 2021 adjusted EBITDA margin of approximately 16%.
Adjusted EBITDA, before a small restructuring adjustment, was $405.8 million, and margin was 17.9%.
Diluted earnings per share were $0.66 as reported and $0.70 as adjusted before the after-tax impact of the amortization of acquired intangibles.
Our net revenue in the quarter was $2.27 billion, an increase of $416.2 million from a year ago.
Compared to Q2 2020, the impact of the change in exchange rates was positive 3.1% with the US dollar weaker against currencies in most of our largest markets.
Net divestitures were negative 40 basis points.
Our organic net revenue increase was 19.8%, which brings us to 10.6% organic growth for the six months.
Our IAN segment grew 20.5% organically.
At IPG DXTRA, organic growth was 15.1%, which reflects some recovery of the events and sports marketing offerings within the segment, the disciplines that have been most significantly impacted by the pandemic.
In the US, which was 63% of net revenue in the quarter, organic growth was 17.4%.
Revenue decreased a year ago in the same period by 8%.
International markets were 37% of our net revenue in the quarter and increased 24.4% organically.
You'll recall that the same market decreased 13.1% a year ago in the second quarter which ranged by region between negative 10% and negative 15%.
Continental Europe grew 27.9% with notably strong growth in Germany, Spain and France.
The UK increased 18.7% organically, led by McCann, DXTRA, media, data and tech and R/GA.
Asia-Pac grew 14% organically.
Our organic growth in LatAm was 49% with exceptional results across the region, including Brazil, Mexico and Argentina.
Our other markets group grew 29.2% with notably strong performance in the Middle East and Canada.
Our operating expenses excluding billable expenses, the amortization of acquired intangibles and restructuring charges increased only 11% from a year ago and to 22.5% growth of net revenue.
The result was second quarter margin expansion to 17.9% from 9.4% a year ago.
We also reduced our real estate footprint by 15% last year.
We are currently seeing the benefit of most of these actions and at a full run rate they will generate $160 million in annual cost savings.
As you can see on this slide, a ratio of total salaries and related expense, as a percentage of net revenue was 65.4%, which has significantly improved from the second quarter of 2020 when revenue had decreased sharply.
Underneath that, we drove very strong leverage on our expense for base payroll, benefits and tax, which was 53% of net revenue in the quarter.
Our severance expense ratio also decreased sharply to only 40 basis points of net revenue, compared to 3% in Q2 2020, which was at an elevated level due to the impact of the recession.
Going the other way, our expense for performance-based incentive compensation increased to 6.4%, consistent with our very strong operating results.
Expense for temporary labor also increased, as a percentage of net revenue to 4.5%, as a result of servicing the top line's quick acceleration.
At quarter-end, total worldwide headcount was approximately 53,000, a 1.4% increase from a year ago and up 5.2% from the beginning of this year, with hiring to support our growth.
Also on this slide, our office and other direct expense decreased as a percentage of net revenue by 380 basis points to 13.3%.
Our occupancy expense decreased to 5% of net revenue, mainly due to the restructuring of our real estate, as well as leverage on our revenue growth.
We leveraged all other office and other direct expense by 220 basis points, which reflects lower expense for bad debt and acquisition costs and leverage as a result of our revenue growth.
Our SG&A expense was 1.3% of net revenue, with the increase from a year ago due to the higher unallocated performance-based incentive expense and increased employee insurance expense, which was at a very low level a year ago.
Our expense for the amortization of acquired intangibles in the second column was $21.6 million.
The restructuring refinement in the quarter is a benefit of $200,000.
Below operating expenses in column four, we had a pre-tax loss in the quarter of $1.7 million in other expenses due to the disposition of small non-strategic businesses.
At the foot of the slide, you can see the after-tax impact per diluted share of these adjustments was $0.04 per share, which bridges our diluted earnings per share as reported at $0.66 to adjusted earnings of $0.70 per diluted share.
Cash from operations was $468.2 million, compared with the use of $87.1 million a year ago.
We generated $101.6 million from working capital compared to a use of $264.9 million last year.
Investing activities was $43.3 million in the quarter, mainly for capex of $34 million.
Financing activities used $101.8 million, mainly for our dividend.
Our net increase in cash for the quarter was $325.6 million.
We ended the quarter with $2.34 billion of cash and equivalents.
Under current liabilities, the current portion of long-term debt refers to our $500 million, 3.75% senior note which matures in October of this year.
Again, we have the maturity in October of this year, and then only $250 million due in April 2024.
One of our many priorities over the years has been the creation and implementation of open architecture solutions, where we bring the best of IPG together in collaborative teams that are customized to client-specific business needs and increasingly a key element of this approach, Open Architecture 2.0, as it were, is Acxiom whose data management expertise and data assets play a role in an increasingly broad range of our offerings.
FCB Health was also named Healthcare Network of the Year and AREA 23 and FCB Health Agency was named Healthcare Agency of the Year.
During the quarter, as part of our integrated ESG efforts, we also announced an action plan that consists of three climate roles, committing to set a science-based target; sourcing 100% renewable electricity by 2030, and joining the Climate Pledge, co-founded by Amazon and Global Optimism.
And they announced that they're committing to invest at least 5% of client budgets in black-owned media by 2023.
We will, of course, be mindful of the public health situation and of the learnings we've accumulated during the past 16 months when it comes to flexible work practices.

Summary:
Diluted earnings per share was $0.66 as reported and was $0.70 as adjusted for the after tax expense of the amortization of acquired intangibles.
With predicated on the continued progress and public health issues, we believe that we can deliver organic growth for the full year of 9% to 10%.
Diluted earnings per share were $0.66 as reported and $0.70 as adjusted before the after-tax impact of the amortization of acquired intangibles.
Our net revenue in the quarter was $2.27 billion, an increase of $416.2 million from a year ago.
At the foot of the slide, you can see the after-tax impact per diluted share of these adjustments was $0.04 per share, which bridges our diluted earnings per share as reported at $0.66 to adjusted earnings of $0.70 per diluted share.