MONTERREY, Mexico--(BUSINESS WIRE)--Fitch Ratings has assigned a 'BB+(EXP)' rating to AES Panama S.R.L.'s (AES Panama) proposed up to USD375 million senior unsecured notes due up to seven years. Concurrently, Fitch has assigned a national scale rating of 'AA-(pan)' to USD375 million senior unsecured notes due up to seven years. AES Panama's ratings are based on the company's strong portfolio of assets with a competitive dispatch position, its multiple power purchase agreements (PPAs) and its ad