Fiona MacLeod, recently appointed as an independent on the board of specialist staffing company SThree, has taken advantage of the shares trading around six-month lows to buy shares in the company.First half results earlier in the month showed profit before tax up 24% but a fall in gross margins from 31.6% to 29.5% and lagging permanent growth may have been a cause for the share selling.But broker Liberum says SThree has the highest contract gross profit growth rate across the sector, with the first half growth achieved despite faster growth in headcount than gross profit through the period. "In order to hit our FY14 forecasts some improvement in perm productivity is required," the broker said. "Nevertheless, SThree's region and sector expansion positions the group to achieve multiples of current profit. We reiterate our 'buy' rating and 475p target price."Top Director BuysVP (VP.) Director name: Mr Neil A StothardAmount purchased: 5,000 @ 662.50p Value: £33,125SThree (STHR) Director name: Ms Fiona MacLeodAmount purchased: 5,000 @ 377.25p Value: £18,862JPMorgan European Inv Trust Growth Shares (JETG) Director name: Ms Josephine DixonAmount purchased: 7,000 @ 221.00p Value: £15,470