(Sharecast News) - London's FTSE 250 was down 0.5% at 20,846.66 in afternoon trade on Thursday.

Opioid addiction treatment maker Indivior jumped to the top of the index as it announced a $100m share buyback programme and said second-quarter results were in line with updated guidance.

IG Group gained even as it reported a drop in full-year profits and revenue, pointing to reduced trading activity.

In the year to the end of May, adjusted pre-tax profit declined 7% to £456.3m, with total revenue down 3% to £987.3m.

Net trading revenue was 10% lower at £844.9m, due to reduced trading activity, it said. IG said weaker OTC derivatives revenue was partly offset by growth in exchange-traded derivatives, with stock trading and investments revenue flat.

Tate & Lyle was in the black as it backed its full-year outlook and said it had made a good start to the new financial year.

On the downside, gold miner Centamin lost its shine despite reporting an improvement in interim EBITDA and an increase in free cash flow as it took advantage of stronger gold prices.

Broadcaster ITV fell as it posted a jump in first-half profits even as revenue dipped, boosted by the Euros and Love Island.

In the six months to 30 June, adjusted pre-tax profit rose to £178m from £118m in the same period a year earlier, while group adjusted earnings before interest, tax and amortisation were up 40% at £213m.

Total revenue edged down 3% to £1.9bn, with growth in total advertising revenue (TAR) offset by an expected decline in ITV Studios revenue, which was hit by the US writers' and actors' strike.

Total external revenue was 2% lower at £1.6bn.

Kitchens and joinery products supplier Howden Joinery lost ground as it said interim profits had only slightly risen as it continued to navigate "challenging" UK market conditions.

FTSE 250 - Risers

Indivior (INDV) 982.00p 18.60%

IG Group Holdings (IGG) 885.50p 4.79%

Crest Nicholson Holdings (CRST) 261.20p 3.00%

Breedon Group (BREE) 406.00p 2.92%

Ithaca Energy (ITH) 126.00p 2.27%

North Atlantic Smaller Companies Inv Trust (NAS) 4,140.00p 2.22%

Tate & Lyle (TATE) 652.00p 1.40%

Renewi (RWI) 656.00p 1.39%

Ninety One (N91) 167.40p 1.33%

BH Macro Ltd. GBP Shares (BHMG) 371.50p 1.09%

FTSE 250 - Fallers

Centamin (DI) (CEY) 122.10p -5.64%

Hochschild Mining (HOC) 173.80p -5.44%

ITV (ITV) 80.00p -5.16%

Endeavour Mining (EDV) 1,714.00p -5.09%

Howden Joinery Group (HWDN) 901.50p -4.85%

Morgan Advanced Materials (MGAM) 317.00p -4.08%

Babcock International Group (BAB) 480.80p -3.84%

Johnson Matthey (JMAT) 1,610.00p -3.82%

Watches of Switzerland Group (WOSG) 401.20p -3.79%

Me Group International (MEGP) 179.00p -3.45%