Companies have increasingly been leveraging their balance sheets, putting them at risk of default in the next 12 to 18 months, according to the analysts at Standard & Poor's. A corporate credit crunch isn't directly linked to the mortgage market, but in the credit cycle the markets tend to move in unison or with one lagging the other. A mortgage-market meltdown would also make it tougher on Main Street and rash of defaults could cause a chain reaction: making it tougher for private equity shops to borrow and buy, slowing mergers and IPOs and shutting down much of Wall Street. http://www.marketwatch.com/news/sto...x?guid={13FFBA8D-EFBF-44F0-BA75-BAF0AFA31CDC}