FRANKFURT, May 11 (Reuters) - Allianz said on Wednesday that it would set aside an additional 1.9 billion euros ($2.00 billion) as it braces for the outcome of U.S. regulatory investigations into a multibillion-dollar trading debacle at its funds arm. ($1 = 0.9489 euros) (Reporting by Tom Sims and Alexander Huebner Editing by Riham Alkousaa)