Staffing firm SThree announced it expects its pre-tax profit for the year to be in line with market expectations, courtesy of a strong fourth quarter performance.The group said its performance in the three months to 30 November was in line with expectations and that it was on track to meet the estimate of £29m in pre-tax profit for the year.Following a 27% increase in gross profit in the fourth quarter, the group expects gross profit for the year to rise 18% to £218m.The company said that full year profit for its Contract division rose 36% in the period and is expected to increase 27% for the year, while gross profit for its Permanent arm was up 16% in the fourth quarter and is expected to rise 6% for the year."We maintained our positive trading momentum in the final quarter, with Contract and Permanent both posting improved performances, to produce an encouraging overall result for the year," said group chief executive Gary Elden."Our investment in Contract and in rebuilding our Permanent capability is now coming through in our results as expected."SThree shares were up 3.31% to 304.75 on Friday.