Revenue of $3.5 billion was the highest quarterly revenue in our company's history.
Revenue increased more than $500 million or 17% year-over-year, and adjusted earnings per share grew 40%.
This demand, combined with our organizational focus on delivering broader value to our clients, was also reflected in a very strong cross-sales, driving our largest revenue synergy quarter-to-date, increasing our run rate by 50% or $150 million sequentially to $450 million.
This sales execution in turn drove a $1.5 billion increase to our backlog, which is now greater than $22 billion.
Our strong execution is driving us to raise both our 2021 guidance and increase our year-end revenue synergy target to $700 million.
In addition, as we consider client demand across our portfolio of solutions, we are extending our mid-term outlook of 7% to 9% revenue growth through 2024.
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In other retail locations where we have rolled out the solution, we are seeing consumers accept premium paybacks offered to pay with points approximately 50% of the time when they are prompted.
The revenue contribution from solutions developed over the past three years continues to grow as a percent of our total revenue mix, up from less than 1% in 2019 to over 4% in 2021.
New solutions also contribute meaningfully to our total revenue growth, with contribution increasing from less than 1% in 2019 to more than 2% in total revenue growth in 2021.
Looking forward, we expect new solutions to drive up to 3 points of incremental growth each year, supporting our outlook for 7% to 9% revenue growth through the midterm.
It's why we are confident in our forward momentum to drive strong 7% to 9% revenue growth through 2024.
On a consolidated basis, revenue increased 17% to $3.5 billion, driven by outperformance in each of our operating segments.
Organic revenue growth was 16%.
Adjusted EBITDA margins expanded 460 basis points to 44%, reflecting strong operating leverage and synergy contribution.
As a result, adjusted earnings per share increased 40% year-over-year to $1.61 per share.
Given our progress and strength of our pipeline, we are increasing our revenue synergy target for 2021 by $100 million to exit the year at $700 million on an annualized run rate basis.
We have more than doubled our initial cost synergy target of $400 million and are on-track to exit the year with approximately $900 million in total annualized savings, including approximately $500 million in operating expense synergies.
We repurchased 2.7 million shares worth approximately $400 million during the quarter, bringing share repurchase to a total of $800 million year-to-date at an average price of $145 a share.
Our leverage ratio declined to 3.3 times, keeping us on-track to end the year below 3 times leverage.
Lastly, we generated free cash flow in excess of $1 billion this quarter, which is the most in our company's history and reflects the highly cash generative nature of our business.
Banking revenue growth accelerated to 8% due in part to strong issuer processing growth of 17% and a 30% increase in Modern Banking platform revenue.
As Gary noted, we had another 2 MBP wins this quarter as well as an add-on sale and MBP revenue will continue to accelerate as more clients go live.
We currently expect MBP revenue growth of nearly 50% for the full year 2021 and for this to further accelerate into 2022.
The Banking segment's adjusted EBITDA margin expanded 410 basis points to 46%.
Capital markets revenue growth also accelerated to 6% this quarter, reflecting strong recurring revenue growth and sales execution.
Capital Markets adjusted EBITDA margin expanded 100 basis points to 46%.
Lastly, for Merchant, revenue growth rebounded sharply to 45% in the second quarter, which includes 10 points of yield benefit and the segment generated its largest new sales quarter in the history of the business.
Merchants' revenue acceleration included 31% revenue growth in e-commerce.
Merchants adjusted EBITDA margin expanded 910 basis points to 50%, primarily reflecting its high contribution margin and synergy benefits.
We now anticipate revenue of $13.9 billion to $14 billion for the full year 2021, which represents an increase of $250 million over our prior guidance.
We now expect Merchant growth to approach 20% this year, ahead of our initial expectations.
Relative to 2019, Merchant revenue growth accelerated 9% in the second quarter or 12% in the U.S.
We're also raising our full year 2021 adjusted EBITDA guidance to $6.125 billion to $6.2 billion and increasing our adjusted earnings per share guidance to $6.45 to $6.60 per share.
For the third quarter, we expect 9% to 10% revenue growth and to generate revenue of $3.49 billion to $3.52 billion.
As a result of the high contribution margins in our business, we expect adjusted EBITDA margin to expand more than 50 basis points sequentially or about 200 basis points year-over-year to approximately 44% for the third quarter.
This will result in adjusted earnings per share of $1.66 to $1.69 in the first year.
Beyond our guidance for the year, we expect to generate 7% to 9% revenue growth in the midterm through 2024, as Gary discussed.
Second, strong new sales and cross-selling activity drove our backlog above $22 billion and increased our revenue synergy attainment by 50% in just one quarter, which will continue to drive future growth into 2022 and beyond.

Summary:
This will result in adjusted earnings per share of $1.66 to $1.69 in the first year.