Lehman was issuing ETNs in UK, Germany and Hong Kong and probably other jurisdictions. Later this went before courts and Lehman lost some judgments as they failed to warn (retail) investors of the risks associated with these ETN like products.I'm not aware if it's ever happened, though.
They are still ETF's and their basket may include futures or options to gain the leverage. Credit risk isn't so much the issue with leveraged ETFs as the roll yield can impact long term holdings.How about those leveraged ETFs?
Almost none. The big risk is that they calculate NAV wrong.