Ladies and gentlemen, thank you for standing by, and welcome to the SS&C Technologies Holdings, Inc. annual meeting. At this time, all participants' lines are in a listen-only mode. I would now like to hand the conference over to your speaker today, Bill Stone, Chairman and CEO. Please go ahead, sir.
Thank you and good morning, everyone. Welcome to SS&C Technologies Holdings, Inc.'s 2020 Annual Meeting of Stockholders. I am Bill Stone, Chairman of the Board of Directors and Chief Executive Officer of the company. In light of the recent public health concerns related to COVID-19, we are holding this year's annual meeting of stockholders through this virtual format. At this time, I'd like to introduce our board of directors. I'm pleased to introduce Normand Boulanger, Smita Conjeevaram, Michael Daniels, Jonathan Michael, David Varsano, and Michael Zamkow. We also have other members of the company's management team who are in attendance with us today, including Rahul Kanwar, President and Chief Operating Officer, Patrick Pedonti, Senior Vice President and Chief Financial Officer, and Joseph Frank, Senior Vice President and Chief Legal Officer. Also joining us in today's meeting are representatives of PricewaterhouseCoopers, which is SS&C's independent registered public accounting firm.
Before we commence the formal portion of the meeting, I would like to touch on two housekeeping matters. First, if you are a shareholder of SS&C and wish to submit a question, you may do so during the meeting by typing the question into the box at the bottom left-hand side of the screen. You must have logged in using your unique control number to submit a question. After we give an overview of the items of business being considered at this meeting, we have allocated approximately 10-15 minutes to answer submitted questions from shareholders relating only to those items of business.
If you have any questions related to SS&C not specifically related to the items of business covered at the meeting, or if your submitted questions are otherwise not addressed, you can reach out to SS&C's investor relations department at investorrelations@sscinc.com, and those questions will be answered in a timely manner. Second, if you are a shareholder of SS&C and logged in using your unique control number, you can also vote your shares during the meeting by clicking on the Click Here button at the bottom right-hand side of your screen. If you have already voted your shares, there is no need to vote again during today's meeting unless you would like to change your vote. The agenda of the meeting should be visible on the lower right-hand side of your screen, and a link to the rules of conduct available under the Meeting Materials section of the screen.
We intend to strictly follow the agenda and rules of conduct in carrying out the business of this meeting. In accordance with the company's bylaws, a copy of the notice of annual meeting of stockholders, proxy statement, and form of proxy has been presented to all stockholders. As chairman of the board of directors of the company, I have been provided with an affidavit from Broadridge Financial Solutions establishing that notice of this meeting was duly provided in accordance with the bylaws. The voting list of stockholders is available for inspection as provided by the company bylaws. These documents will be filed with the corporate records of the company. As we have done in the past, the formal meeting will be conducted first, after which I'll make a few remarks about SS&C's business and financial performance during the past fiscal year.
Following my remarks, I will answer shareholder questions about today's meeting as well as about SS&C's business. Please note that any remarks that we make today about future expectations, plans, and prospects for SS&C constitute forward-looking statements under the federal securities laws. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including those discussed in the Risk Factors section of our most recent annual report on Form 10-K, which is on file with the SEC and available on our website. SS&C has appointed Broadridge Financial Solutions to act as inspector of election for this meeting, and Tracy Oates, a representative of Broadridge, is participating in today's meeting. Ms. Oates has signed her oath of office, which will be on file with the records of this meeting.
I have been informed by the inspector of election that the holders of 235,644,929 shares of common stock of the company are present in person or by proxy. This represents approximately 92.02%, which constitutes a majority of the total issued and outstanding shares of common stock of the company entitled to vote at this meeting. Based on that report, I declare that a quorum is present and that this meeting is duly constituted and convened and is competent to proceed with the transaction of business. Mr. Frank, Chief Legal Officer, will serve as the secretary of the meeting and will prepare the minutes of the meeting. As indicated in the proxy statement, there were three proposals to be acted upon at this meeting. Proposal one is to elect the following three nominees as Class I directors for a term scheduled to expire at the 2023 annual meeting, Normand A.
Boulanger, David A. Varsano, and Michael J. Zamkow. Proposal 2 is to approve in an advisory vote on the compensation of our named executive officers. Proposal 3 is to ratify the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for fiscal 2020. Each of these proposals is more fully described in the proxy statement, and each is recommended by the board of directors. There are no other proposals to come before this meeting, since management has not made any other proposals. No other proposals were submitted by stockholders in the manner prescribed by the company's bylaws, which require that certain information concerning stockholder proposals be provided to the company before the date of this meeting. The polls are open for voting on the three matters that have been presented. If you have already voted, you need not vote again at this meeting.
If you have not voted or would like to change your vote, you may do so by clicking the Click Here button on the bottom right-hand side of your screen. We will attempt to answer stockholder questions submitted through the web portal relating to the items of business being voted on at this meeting after my remarks concluding the voting. As a reminder, you must have logged in using your unique control number to submit a question. It is now 9:10 A.M. Eastern Standard Time, and I hereby declare the polls open for voting. We will now pause for one minute to allow stockholders who wish to cast votes to do so. 9:11 A.M. Eastern Standard Time, and I hereby declare that the polls are now closed. Will Mr. Frank please present the preliminary results of the voting?
Thank you, Mr. Chairman. The preliminary results from the Inspector of Elections are as follows. With respect to proposal number one, the election of directors, a plurality of the votes cast has been voted for the election of each of the three nominees. With respect to proposal two, the advisory vote to approve of the compensation of our named executive officers, a majority of the votes cast has voted against the proposal. With respect to proposal number three, the ratification of PricewaterhouseCoopers LLP as independent registered public accounting firm of the company for fiscal 2020, a majority of the votes cast has voted in favor of the proposal. I turn the meeting back over to you, Mr. Chairman.
Thank you, Mr. Frank. Based on the preliminary report of the Inspector of Election, each person nominated for election as a director has been elected to serve as a director until the 2023 annual meeting. The advisory vote on the compensation of our named executive officer has not been approved, and the Audit Committee's selection of PricewaterhouseCoopers LLP as independent registered public accounting firm for fiscal 2020 has been ratified. These actions will be recorded as stated in the minutes of the meeting. This concludes the formal matters to be acted upon at this meeting. I declare this meeting closed. I would now briefly like to discuss SS&C's business and financial performance. SS&C had an excellent 2019, and I believe that we will continue to work hard for our shareholders in 2020. We have a few things that I'd just like to go over.
SS&C's been around since 1986. We currently employ almost 23,000 people in 93 cities and 35 countries globally. We have been public since the first quarter, actually March 31st, 2010. We have over 18,000 clients, and we have 96.2% of our last 12 months revenue has been retained. For COVID-19, we have done a number of things. The most important thing is to take care and safety of our employees, and then also to be able to continue to deliver service to our clients. I'm pleased to report that our clients' feedback has been very positive. We also have shown that our disaster recovery procedures and our business continuity plans have been executed, and they have worked as expected. For the first quarter of 2020, which ended March 31st of this year, we had an excellent quarter.
Our revenues were $1.178 billion. Our adjusted operating income was $444 million. Our adjusted consolidated EBITDA was $463 million, and we had operating cash flow of $147 million. We're a highly diversified business. About 34% of our business comes in through the alternative investment space, and that includes hedge funds, fund of funds, private equity funds, real estate investment trusts. We have about 38% coming from institutional business, which would be large-scale institutional customers, such as large-scale mutual funds, large-scale insurance company, large-scale bank. We have healthcare is about 9%, wealth management's about 13%, we have a number of specific client services and products that represents about 6%. We're one of the largest financial technology and services firms in the world, and we have a number of things that we do. 75 of the top 100 hedge funds use us.
We help our clients file regulatory reporting on over $2 trillion in assets. We have over 56 million transfer agent accounts, and we are used in 999 of the Fortune 1,000 treasury departments. We're a pretty big place. We have a lot of clients. We do a lot of things for them, and it's worked out pretty well. We also have been able to build new products and services, including things like a waste, fraud, and abuse application for our healthcare pharmacy benefit claims payment business. We also have put out a SS&C Singularity. We have an enhanced client portal. All of these things we've done over the last couple of years. In 2019, we spent over $380 million on research and development.
We also have done, I think, 56 or 57 acquisitions in the last 25 years, we continue to focus on great assets that we can bring into our company. Our most recent one was Innovest. It's a New York-based, primarily trust accounting business. They also do some payments. They also have things for unique asset accounting, such as oil and gas. We are still primarily a North American-based company. We have approximately 75%, 76% of our business comes from the U.S. and Canada. We have 19% in Europe, Middle East, and Africa. We have a growing presence in Asia Pacific. We have a high margin business model with EBITDA margins, operating margins of 39%. We have grown our revenue from our public days of, first year of public 2010 of $329 million to 2019 of $4.669 billion.
We also pay down debt quickly. Since our acquisition of DST Systems in April of 2018, we've paid off more than $2.1 billion in debt. We've had a compound annual growth rate in our adjusted diluted earnings per share since our IPO in 2010 of 26.9%. At 26.9%, that grows our earnings per share from $0.45 per share in 2010 to $3.83 in 2019. We have a sticky customer base of 96%. We have very strong cash flow characteristics. We generated over $1.3 billion in cash flow. We're very well known in the markets that we serve. We are also very focused on shareholder friendliness. That is who SS&C is. Again, we appreciate you coming to our shareholder meeting. With that, if there aren't any questions, I believe this concludes the meeting.
Thank you for all coming to our 2020 Virtual Shareholder Meeting, and I look forward to seeing you in 2021. Thank you.
Thank you. That concludes today's conference. You may now disconnect.