President Barack Obama's guarantee on $1 billion of Egyptian Eurobonds is poised to reduce the country's borrowing costs, helping the transition to democracy after six decades of autocratic rule. The support that Obama pledged last month may cut yields on the five-year debt by 200 basis points, or the equivalent of $100 million, according to the median estimate of five fund managers surveyed by Bloomberg. Yields on Egypt's one-year bills jumped to the highest level since November 2008 following the uprising that ousted President Hosni Mubarak in February. The country last sold international debt in April 2010. "The American backing...