Looking into the current session, Citigroup Inc. (NYSE:C) shares are trading at $67.12, after a 0.1% gain. Moreover, over the past month, the stock spiked by 11.40%, but in the past year, fell by 2.75%. Shareholders might be interested in knowing whether the stock is undervalued, even if the company is performing up to par in the current session.

The stock is currently above its 52 week low by 16.93%. Assuming that all other factors are held constant, this could present itself as an opportunity for investors trying to diversify their portfolio with Banks stocks, and capitalize on the lower share price observed over the year.

Most often, an industry will prevail in a particular phase of a business cycle, than other industries.

Compared to the aggregate P/E ratio of the 12.2 in the Banks industry, Citigroup Inc. has a lower P/E ratio of 6.36. Shareholders might be inclined to think that the stock might perform worse than its industry peers. It's also possible that the stock is undervalued.

P/E ratio is not always a great indicator of the company's performance. Depending on the earnings makeup of a company, investors can become unable to attain key insights from trailing earnings.