Good day, and welcome to the 2016 MSCI Annual Meeting of Shareholders. I would now like to turn the conference over to Henry Fernandez, Chairman and CEO. Please go ahead.
Good afternoon, and welcome to the 2016 Annual Shareholders Meeting for MSCI Inc. The polls are now open and you may submit your vote online beginning at this time until we officially close the polls following the formal presentation of the proposal. Please remember that if you have already submitted a proxy, it is not necessary to submit your vote online unless you wish to change your vote. It is now 2:30 p. M.
And this meeting is officially called to order. I am pleased that most of the members of our Board of Directors are with us for the meeting this afternoon. Let me introduce the directors who are participating in today's meeting. Rob Ash, Dan DuFarn, Wayne Edmonds, Rob Hale, Alice Handy, Kathy Kinney, Wendy Lane, Linda Grifler, Pat Journey and Skip Vale. Skip has been our Lead Director since 2010.
At our meeting today, I will present the proposals that you're voting on. If you have any questions about the proposals, you may submit them through the web portal. Following the presentation of all proposals, any questions about them will be addressed. Then we will hear the preliminary report of the Inspector of Elections and adjourn the formal annual meeting. I will then proceed with a brief on our 2015 results and our Q1 2016 results released this morning.
After that, we have reserved time for questions not regarding the proposals. Our meeting rules require shareholders wishing to raise questions on topics other than the proposal to wait until such time. At this time, I would like to note that Jonathan Gradlek, who is a partner at PricewaterhouseCoopers is also participating and is available to answer your questions. Broadridge, the Inspector of Elections for this meeting is represented here today by Christopher Woods. The Board of Directors fixed March 2, 2016 as the record date for determining the shareholders entitled to vote at this meeting.
And as stated, it's with the Inspector of Elections, attesting to the fact that the notice of meeting, the proxy statement and the 2015 annual report to shareholders were mailed to those shareholders of record on March 18, 2016. Now I will present the 5 items to be voted upon. As a reminder, we will acknowledge any comments or questions submitted by stockholders on the proposals themselves after all proposals have been presented. Item 1 is the election of directors. The current Board has nominated 12 directors, myself, Henry Fernandez, Rob Ash, Ben DuPont, Wayne Edmonds, Rob Hale, Alice Handy, Kathy Kinney, Wendy Lane, Linda Riffler, George Sigler, Art Journey and Skip Valley.
Item 2 is the advisory vote to approve the compensation of our named executive officers as described in the proxy statement. This vote, which is often called a say or pay vote, is a non binding vote. Although the compensation committee and the full Board will certainly take the results of the vote into account when making future compensation decisions. Item 3 is the vote to approve our 2016 Omnibus incentive plan and the material terms of the performance goals under the plan for purposes of Section 162 of the internal revenue. Item 4 is the vote to approve our 2016 non employee directors' compensation plan.
And finally, item 5 is the ratification of PricewaterhouseCoopers as MSCI's independent auditor. All of the proposals on the agenda are now before the meeting. If any shareholder has a question or would like to make a comment regarding any of the proposals and you have not done so already, please submit your questions through the web portal. Since there are no questions or additional proposals to come before the meeting relating to the business of the meeting as set forth in the agenda, this is your final opportunity to vote. Any shareholder who has not voted or who wishes to change his or her vote may do so by following the instructions on the web portal.
The voting is now ended and the polls are now closed. The next agenda item is the preliminary report of the Inspector of Elections. Rick Bogdan, our Corporate Secretary, will summarize the report.
Thank you, Henry. The preliminary report of the Inspector of Elections indicates that approximately 90.88% of the votes of common stock voted for or against the director nominees, each case representing a majority of such votes, have voted for the director nominees. Approximately 96.38 percent of the votes of common stock represented at this meeting have voted to approve our compensation practices. Approximately 95.39% of the votes of common stock represented at this meeting have voted to approve our 2016 omnibus incentive plan and material terms of the performance goals under the plan for purposes of 162 ms of the internal revenue code. Approximately 96.48 percent of the votes of common stock represented at this meeting have voted to approve our 2016 non employee directors' compensation plan.
Approximately 96.76% of the votes of common stock have voted to ratify our audit committee selection of PricewaterhouseCoopers, LLP as the company's independent auditor for 2016. Any ballots cast before the polls close but not reflected in the preliminary report will be reflected in the final vote tally and we will file a report with the SEC containing the final tally. That summarizes the preliminary report of the Inspector of Election.
Thank you, Rex. This concludes the formal part of our annual meeting. There being no further business to come before the meeting, the 2016 Annual Meeting of Stockholders of MSCI Inc. Is now adjourned. And now I will provide a brief report about the company's 2015 financial results and 2016 Q1 results.
For the remarks today, I will provide you with a strategic update on MSCI and review our results for the year 2015 and the Q1 of 2016, which I said before were released earlier today. Then I will highlight for you the research enhanced content that is at the very core of MSCI. How we are striking the right balance of investing for growth and at the same time focusing on profit margins the long term target that we have set for the company and lastly, our capital return efforts and the framework we use to allocate capital. Please turn to Slide 4 for a strategic update on MSCI. We are a growth company and as such we're constantly innovating in order to catch the next wave of growth in the investment industry.
We have several levers to drive our future growth across our segment, including continued strong growth in index, improving profitability in analytics and a combination of a strong growth and improving profitability in our other all other segments, which is ESG and real estate product lines. In terms of operational efficiency, we are relentless in our focus on ensuring that our cost base is right sized and aligned with the most attractive investment opportunity. We are gaining increasingly greater visibility and insights into the drivers of our cost base through our new segment reporting and activity based costing. Our tax planning work is on track to deliver further improvement in our operating tax rate in the quarters to come. We have a very shareholder friendly capital return plan and through March 31, 2016, we have returned US1.7 billion dollars to shareholders since 2012 through share repurchases and cash dividends.
Lastly, in terms of management strength, with our CFO, Bob Cuto retiring, we have been fortunate to recruit Kathleen Winters as our new CFO, who starts with the company on Monday and we provided a release on her joining last night. Kathleen joins MSCI from Honeywell International where she most recently served as Vice President and Chief Financial Officer for the company's $9,000,000,000 Performance Materials and Technologies Division. In her 14 years with Honeywell, Kathleen played a key role in partnering with company leadership to drive business growth and profitability. On Slide 5, we show how well we're executing and we have executed in 2015 with a summary of our full year 2015 results. Revenues increased 8% for the full year.
These strong results were driven principally by index products, which posted double digit revenue increases in both subscription and asset based fees. Disciplined expense management across the company limited total operating expense growth to 2%, which resulted in a 3 80 basis points increase in our adjusted EBITDA margin to 45%. And we lowered our effective tax rate by over 100 basis points. We returned throughout the year approximately 7 $60,000,000 in capital to investors through share repurchases and dividends. We increased our quarterly cash dividend by 22% to $0.22 per share or $0.88 per share on an annualized basis.
And we raised $800,000,000 from the private offering of our 5.75 percent senior notes due 2025. So in summary, we delivered strong results in 2015, but we're not standing still. We are continuing to execute on our growth strategy in 2016. This was reflected with our solid Q1 2016 results as shown on Slide 6, where we continue to build on the momentum that we established in 2015. A 6% increase in revenue driven by double digit growth in index recurring subscription revenues, accompanied by a 6% decline in adjusted EBITDA expenses drove a 24% increase in adjusted EBITDA.
These strong operating results combined with a lower effective tax rate and a large shares repurchase program drove a 36% increase in adjusted EPS. On Slide 7, at our core, MSCI is a technology enabled content company that leverages and shares content across the entire MSCI ecosystem to innovate new products and services. We deliver our content to our clients in the form of indices, risk models, ESG research, real estate benchmark, etcetera. All of our products, applications and services are designed to help our clients optimize the use of our content. Our content sits at the very center of our clients' investment processes.
It provides them with the insights and the tools they need to build and manage their complex and global portfolios. It is easy to look at our business in the way we present ourselves in financial reporting, index, analytics, ESG, real estate, But content is a unifying element and it will be our ability to integrate that content across all of our products and services that will unlock incremental levels of growth for MSCI. On Slide 8, we highlight where we are in terms of the cycle of investing for growth and profitability at the same time. As our overall operating profit margins have expanded due to continued solid revenue growth and improved profitability in analytics, we are continuing to invest to drive future growth. Our long term target for the company and each of the segments reflect a balanced level of investment that allow us to continue to innovate and sell our products and services.
While we will increase investment for the remainder of 2016 relative to the quarterly run rate of the Q1, we're also focused on profitability as reflected in the lowering of our full year 2016 adjusted EBITDA expense rate. On Slide 9, we highlight our long term targets for the company. In our core index segment, where MSCI's global and international equity indices are considered the gold standard for global investing, is our long term goal to grow revenues annually in the low double digits with targeted adjusted EBITDA margin ranging from 68% to 72%. In analytics, our long term target to move from being a low revenue generator in the low to mid single digits to a medium revenue grower in the upper single digit over the long term. It is also our long term target to move adjusted EBITDA margin into the range of 30% to 35%.
Our clients increasingly rely on our products to meet the demands an ever increasing complex and fast moving multi asset class investment process. Lastly, in our all other segment, which consists of our ESG and real estate product line, we're now seeing high growth opportunities in our ESG products and the potential to achieve higher levels of growth and profitability for our real estate product line. Our long term target is for the all other segment to be an engine of future growth and we hope to have the segment move from being a medium or upper single digit grower to a high or low double digit grower over the long term. Our long term target is to have adjusted EBITDA margins move from negative levels to the range of 15% to 20%. We anticipate that the respective contribution from each of the segments that I have just outlined will help us achieve our long term goal of moving the entire company from upper single digit revenue growth, the lowest double digit level that we aspire to.
And to do so profitably with EBITDA margins of approximately 50%. On Slide 10, we have an update on our capital return efforts. Now that we have paid incentive compensation and taxes at the beginning of the year and excluding the upcoming dividend, we have approximately $200,000,000 in excess cash. We have delivered on our commitment to not store capital. And as our cash balances have declined to more normal operating levels, we have now even more flexibility to be more opportunistic with our share repurchases.
And we expect to repurchase more shares at lower prices and less at higher prices. Capital deployment is a dynamic process that is constantly being evaluated with our Board against various competing users. As we begin to explore the possibility of adding additional leverage, given our target of gross leverage in the 3x to 3.5x level and as we continue to delever, we want to ensure that we maximize that every dollar deployed as an appropriate return for our shareholders on those dollars way exceeding our cost of capital. Given this on Slide 11, we highlight the hierarchy of uses of capital that support our capital allocation strategy. Our first dollar goes to high return organic investments, then followed by inorganic investments, principally small bolt on acquisitions, if we can find them and if they produce if they show high rates of return.
Next, capital return to our shareholders through the most effective and accretive method. And lastly, depending on the environment, the repayment of debt is necessary. Our Board of Directors is keenly focused on this capital allocation framework to ensure that we achieve the highest return on our capital and equally the most optimal capital base. We will now proceed with your questions and answers, if any. So if you have any questions, please enter it into the appropriate box on your screen.
Okay. Since there are no questions relevant to the business of the company, we will conclude the meeting and we thank you very much for your interest in MSCI.