Just before fraud charges against Goldman Sachs (NYSE: GS) sent financials into a tailspin, Citigroup (NYSE: C) managed to crack through the $5-per-share barrier. Fools know that share price by itself doesn't mean much, but $5 a share is often considered a minimum share price for many institutional investors and mutual funds.

In Citi's case, the stock is definitely underowned among institutions and mutual funds compared with its peers:

Bank

Institutional and Mutual Fund Ownership

Citigroup

36%

Bank of America (NYSE: BAC)

56%

JPMorgan Chase (NYSE: JPM)

75%

Wells Fargo (NYSE: WFC)

76%

Goldman Sachs

74%

Morgan Stanley (NYSE: MS)

77%

Source: Yahoo! Finance.

With more than 28 billion shares outstanding, Citigroup would have to see institutions and funds buying more than 5.6 billion shares just to see it bump up to the same ownership level as Bank of America. Getting to a level comparable to the other big banks would mean those big buyers would need to pick up about 11 billion shares.

Consider two points before you rush out to buy Citi ahead of those institutions. First, just because the pros can buy Citi, that doesn't mean they will. Second, there's a big seller out there: The U.S. Treasury holds 7.7 billion shares through TARP and has announced that it will be selling them over the course of 2010.

To get a handle on how Citi compares with its peers on a fundamental basis, let's look at the range of price-to-earnings ratios based on analysts' high and low 2011 earnings estimates for each of the banks we've already considered.

Bank

2011 Low Estimate

2011 High Estimate

P/E Low

P/E High

Citigroup

($0.05)

$0.55

N/A

8.3

Bank of America

$0.95

$2.50

19.4

7.4

JPMorgan Chase

$3.81

$5.40

15.2

8.4

Goldman Sachs

$17.50

$24.02

9.2

6.7

Morgan Stanley

$2.50

$4.05

12.5

7.2

Wells Fargo

$1.80

$3.86

18.1

8.4

Sources: Yahoo! Finance and author's calculations.

Citi has the highest percentage spread between the high and low estimates, but it trades in line with or at a premium to its peers based on its high estimates. In other words, investors who want to own a bank stock should think Citi will do better than the most optimistic analyst on Wall Street predicts before picking it over one of the other big banks.

Breaking through the $5 barrier may bring some Citi buyers to the market, but any new buyers are only likely to be enough to absorb the treasure trove of Treasury's shares. Valued on optimistic future earnings, Citi trades in line with its peers, but the wide range of estimates points to a higher risk that earnings will fall short.

What's your opinion? Is Citi at $5 cheap or expensive?

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Fool contributor Russ Krull owns shares of Wells Fargo but has no financial position in any of the other companies mentioned in this article. The Fool has a disclosure policy that's always worth a premium valuation.