Moody's shocked bond investors this week with a surprise two-notch downgrade that put Brazilian oil company Petrobras in junk territory. The move was seen by some investors as overly assertive, leaving them to add exposure incrementally. "It was aggressive," said Jack Deino, head of emerging market portfolio management and senior portfolio manager at Invesco. "It just reflects the rating agencies' proclivity to shoot from the hip. In late January, Moody's demoted the company to Baa3 from Baa2, warning more ratings actions were on the horizon if the company failed to release audited results. It stuck to its word, exceeding expectation with a cut to Ba2 late on Tuesday. So far, the massive wave of forced selling out of high-grade account portfolios has yet to truly transpire.