When it comes to investing, going with the crowd will rarely -- if ever -- make you rich. If your objective is to buy low and sell high, then, in the words of Warren Buffett, you must be "greedy when others are fearful and fearful when others are greedy." This is the foundation of contrarian investing.

But there's a twist. To be a contrarian investor, you must first know what to be contrary to. And this is where the SEC's invaluable EDGAR database comes in. Every quarter, companies and large institutional investors are required to disclose their equity holdings. By patching these together, we can get a fuller picture of a particular stock's popularity.

What follows, in turn, is a look at the principal owners of Citigroup's (NYSE:C) outstanding common stock.

A broad overview
As you can see in the following chart, the majority of Citigroup's three billion shares are held by institutional investors. Company insiders, including board members and corporate executives, own a further 0.16% of the outstanding common stock. And the public at large owns the remaining 32%.

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Source: S&P's Capital IQ.

Institutional investors
Digging in a big further, the largest institutional stakeholders in Citigroup are bond giant BlackRock, followed by The Vanguard Group, the asset management arm of State Street, Capital Research and Management Co., and Fidelity Investments.

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Source: S&P's Capital IQ.

The largest buyers have been Columbia Management Investment Advisers and Marsico Capital Management, which have recently acquired 14.7 million and 11.8 million shares of common stock, respectively. Meanwhile, the two largest sellers of late have been Capital Research and Management Co. and Goldman Sachs (NYSE:GS), which have disposed of 28.7 million and 11.2 million shares, respectively.

Biggest insiders
Turning to inside investors, the largest inside owner is Manuel Medina-Mora, Citigroup's co-president. The second largest holder is Vikram Pandit, the former chief executive officer. And the third largest holder is John Havens, the bank's former president and chief operating officer.

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Source: S&P's Capital IQ.

The Foolish bottom line
While insider and institutional ownership together represent only one metric, it's nevertheless an important one. Beyond hinting at the overall market's sentiment toward a stock, it also gives investors insight into the confidence of the people best positioned to predict a company's current state and future success.

John Maxfield has no position in any stocks mentioned. The Motley Fool recommends Goldman Sachs. The Motley Fool owns shares of Citigroup. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.