Moody's assigned a B2 corporate family rating and B2-PD probability of default rating to PAREXEL International Corp.

The outlook is stable.

Moody's said the B2 rating is constrained by the high financial leverage resulting from the leveraged buyout. The ratings are also constrained by inherent volatility in the contract research organization industry that can lead to project cancellations.

The B2 rating is supported by the company's good scale and breadth of service offerings in the contract research organization industry. It is also supported by the rating agency's expectation for very good liquidity and positive free cash flow.

Moody's said the stable outlook reflects its expectation that PAREXEL's leverage will remain high but its free cash flow will be positive and liquidity will remain good.