A potential sale of Subway is hampered by rising interest rates and concerns about an economic slowdown, making debt more expensive and less available for buyout firms. Subway’s financial adviser JPMorgan Chase ($JPM@US), has put forward a $5 billion debt financing package to show buyout firms they can borrow enough to structure an attractive deal. Bids for the company have ranged between $8.5 billion and $10 billion. More than 10 private equity firms have submitted second-round bids.