third-quarter earnings rose 50% from a year ago, driven by a 9% sales gain and a one-time tax benefit, but the company said it would struggle to hit fourth-quarter profit targets.

Lexmark earned $156.1 million, or $1.17 a share, in the three months ended Sept. 30, compared with earnings of $104.1 million, or 79 cents a share, last year. The 2004 quarter included a tax benefit of 15 cents a share, before which the company earned $1.02 a share. Revenue rose 9% from a year ago to $1.27 billion.

Analysts were forecasting earnings of 98 cents a share on revenue of $1.29 billion in the most recent quarter.

For the fourth quarter, Lexmark expects to earn $1.05 to $1.15 a share. Analysts surveyed by Thomson First Call were expecting earnings of $1.15 a share. The quarter is expected to include a gain of 5 cents a share related to an adjusted tax rate and roughly 7 cents to 8 cents of additional marketing expense.

Gross profit margin was 35.2% in the latest quarter compared with 32.1% a year ago, while operating income margin improved 2.5 percentage points to 14.6% in the third quarter.