Numis Securities has shifted its rating on broadcaster and producer ITV from 'buy' to 'add' following the recent strong performance by the stock.ITV underwhelmed investors on Thursday despite saying that advertising revenues will be up 5% in the first half, ahead of Numis' +1% forecast."Advertising was +12% in Q1 aided by the phasing of Easter. We had expected Q2 to be impacted by the phasing of Easter, disruption from the Election and the absence of the World Cup. However, April was +5%, May -5% and June down 5-7% to give Q2 -2%," Numis said.With the company to benefit from the Rugby World Cup in the autumn amid the positive UK macro backdrop, the broker said it sees upside to advertising revenue estimates for the full year.It has raised its full-year growth forecast from 3% to 5% and lifted its target price from 275p to 290p."We raise our target price [...] though after their strong recent run we now rate the shares as an 'add' (was 'buy')," Numis said.The shares were down 1.8% at 255.3p by 10:59.