Two months after a new CEO took the reins at LyondellBasell, the Rotterdam-based company with business headquarters in Houston, Texas, is looking for a new CFO.

LyondellBasell said it has reached a separation agreement with its chief financial officer, Karyn Ovelmen, who will continue in her current role for up to three months while the company searches for a successor.

No reasons were disclosed for the separation. Some observers said it could be related to a weaker than expected performance in the fourth quarter of 2014, when revenues fell back 7.6% - more steeply than expected - and the company was hit by a heavy inventory-adjustment charge. Record earnings were reported for the full year, however.

Ovelmen joined LyondellBasell in 2011, replacing the retiring Kent Potter. Previously, she was CFO of European petroleum refiner Petroplus Holdings and held other positions in the energy sector.

In December, 2014, Bhavesh V. (Bob) Patel, previously executive vice president of the LyondellBasell olefins and polyolefins business segment, replaced James L. Gallogly in the top job.

In announcing Ovelmen's impending departure, Patel said: "Karyn has seen the Company through a financial transformation, during which we have improved our balance sheet, obtained investment grade ratings, and instituted a capital deployment plan that has returned significant value to our shareholders. We wish Karyn much success in her future endeavors."