Timing the market is tough in the best of times; lately it’s become next to impossible. Just ask Stephen Jennings.

The founder and controlling shareholder of Moscow-based investment bank Renaissance Capital rebuffed a takeover attempt by Russia’s VTB Bank a year ago, when some analysts were estimating RenCap’s value at as much as $4 billion.

Over the past six months, Jennings has held talks with billionaire Mikhail Prokhorov. Those negotiations took on an urgent air last month as the global credit crisis whipsawed Russia, sparking massive capital flight, a stock market plunge and frantic government efforts to shore up the country’s banks. Seeking shelter from the storm, Jennings agreed to...