Investment banking can be a volatile segment of the economy, especially when the stock market is in a state of turbulence itself. But companies that have proven an ability to navigate these treacherous waters can be big winners for your portfolio. Evercore Partners (NYSE: EVR) is such a company.

Evercore’s Investment Banking business advises its clients on mergers, acquisitions, divestitures, restructurings, financings, public offerings, private placements and other strategic transactions and also provides institutional investors with high quality equity research, sales and trading execution that is free of the conflicts created by proprietary activities.

Meanwhile, Evercore’s Investment Management business comprises wealth management, institutional asset management and private equity investing.  The firm serves a diverse set of clients around the world from 28 offices in North America, Europe, South America and Asia. Evercore was founded in 1996 by Roger Altman (a senior Treasury Department official in the Clinton administration), David Offensend, and Austin Beutner.

In 2010 the firm advised on the two largest initial public offerings of the year—including the General Motors IPO. In the same year, the firm added a Private Funds placement group, and launched a research-driven equity sales and trading business. It ranked 11th in 2010 in the volume of announced transactions as compared to all firms, including bulge bracket and universal banks. The firm grew its Latin American presence through its 2010 acquisition of a 50% interest in Brazil-based G5 Advisors.

Evercore’s biggest news of late is that it has completed the acquisition of the ISI International Strategy & Investment and the remainder of its legacy Institutional Equities business.

The acquisition positions Evercore as an elite and scaled provider of non-proprietary capital markets advice and execution, broadening Evercore’s Investment Banking business and expanding its growth opportunities. The business, Evercore ISI, will initially provide macro research, as well as fundamental research coverage of more than 600 companies across 12 industries, or approximately 60% of the combined market cap of the S&P 500.

Evercore ISI will serve more than 1,500 institutional investors globally, including the largest asset managers and fund complexes in the world.

“We are excited to announce the closing of the ISI transaction, moving us one step closer to our goal of creating the most elite independent investment banking advisory firm in the world,” said Ralph Schlosstein, President and Chief Executive Officer. “While it is still early days, client feedback to date affirms our expectation that Evercore ISI will have a positive effect on the growth rate of our overall Investment Banking business and that the Equities business will be an attractive business in its own right. Since the announcement of the acquisition in August, ISI has achieved a #5 ranking for its research product from Institutional Investor, and the firm has had record revenues in September and October, reflecting the support for this transaction from institutional investors globally. We are excited to welcome the entire ISI team to Evercore.”

“This step creates a broader and more effective banking firm because it provides Evercore with premier skills in all aspects of equities,” said Roger Altman, Executive Chairman. “I look forward eagerly to working with our new ISI colleagues.”

“Our clients’ support for this transaction has been extremely positive,” said Ed Hyman, Evercore ISI’s Chairman. “The combination of talent from the ISI and Evercore Equities businesses has created a powerhouse in research and distribution and we look forward to continuing to serve our expanded client network with the highest quality independent research, analysis and advice.”

In August 2011, the firm completed its acquisition of Lexicon Partners, an independent UK-based investment banking advisory firm. In October 2011, Evercore and Kotak Mahindra Capital Company Limited announced that the two firms had entered into an exclusive strategic alliance for cross-border M&A advisory services between India and the United States, the United Kingdom, and Mexico. In November 2011, the firm announced that it had agreed to purchase a 45% non-controlling interest in ABS Investment Management, an institutionally focused equity long/short hedge fund of funds manager.

With all this expansion, the stock seems well-poised for further growth. Yet the stock price is actually noticeably lower than it was on June 1. The stock suffered a steep decline in June after a relatively disappointing earnings report and has not fully recovered, despite the recent good news about the ISI acquisition.

Evercore seems to be seriously undervalued at this point. Its price-earnings ratio is about 27 and its market cap is $1.85 billion. We think it’s a buy up to 58.

Tom Scarlett is an investment analyst for Personal Finance.