By David Randall and Jeffrey Hodgson NEW YORK (Reuters) - Tom Sowanick, a three-decade veteran of the investment business, returned from a trip to Greece this week with a "very sobering view" of its debt crisis: he now expects the country to default on its obligations and leave the euro zone. The founder of New Jersey-based Ahilio Investment Advisors is among a minority of U.S. investors who expect the current tensions between Greece and its creditors to result in a so-called "Grexit", and who are preparing for a potentially major hit to European and U.S. markets. Investors in the United States have been mostly sanguine over the worsening Greek crisis so far.