Derivatives that helped inflate the 2007 credit bubble are beingremade for a new generation.

JPMorgan Chase & Co. is offering a swap contract tied to aspeculative-grade loan index that makes it easier for investors towager on the debt. Goldman Sachs Group Inc. is planning as much as10 billion euros ($13.4 billion) of structured investments thatbundle debt into top-rated securities, while ProShares last weekstarted offering exchange-traded funds backed by credit-defaultswaps on company debt.

Wall Street is starting to return to the financial innovationthat helped extend the debt rally seven years ago beforeexacerbating the worst financial crisis since the Great Depression.The instruments are springing back to life as investors seek newways to boost returns that are being suppressed by central bankstimulus. At the same time, they're allowing hedge funds and otherinvestors to bet more cheaply on a plunge after a 145 percent rallyin junk bonds since 2008.