i'm also not sure what you mean. how does the speculative bubble come from the government guaranty? doesn't the guaranty make it intrinsically _less_ speculative? FFELP loans also have fixed interest rates. less common in private (not govt-backed) student loans.

another thing to consider would be the Obama administration's clear intention to end FFELP in favor of direct federal lending and other programs (no middleman bank's balance sheet involved, so no need to securitize)