Both professional employer organization revenue and temporary staffing net revenue rose at Barrett Business Services Inc. (NASD: BBSI). Fourth-quarter net revenue rose 27 percent to $144.5 million, according to preliminary results released by the firm.

The company also announced it will record an increase to its self-insured workers’ compensation reserve of approximately $5.1 million. Including this expense, Barrett expects to post diluted earnings per share in the fourth quarter of between 71 cents and 73 cents. Excluding the increase, diluted earnings per share would range from $1.13 to $1.15. The expense is the result of increased estimated reserves for prior year injury claims, primarily in the state of California.

“2013 was a very successful year for BBSI as our company matured significantly over the past 12 months," said President and CEO Michael Elich.

“Part of this organizational maturation is to bring greater predictability to the model,” Elich said. “One area of focus is how we consistently review our reserving practices for our workers’ compensation liabilities, while remaining aligned with our actuarial firm.”