Nomura has reduced its full-year revenue assumptions for advertising and marketing group WPP as growth in April appears to have slowed slightly after a stronger first quarter. "The trading statement for the first four months of the year showed organic growth of 6.2% vs. 6.7% for Q1 [first quarter] 2011. This implies April growth was less than 5%, meaning there has been a downward slope since the start of the year," the broker said.Combined with tougher comparatives ahead, Nomura now considers a sub-5% growth rate more likely. The organic growth forecast for the full year is cut from 6% to 4.7%. However, a 'buy' rating and 1,000p target price are retained.UBS has upgraded its target price for polymers manufacturer Victrex by more than quarter, but has kept its 'sell' rating, saying that the current valuation remains too high.The target price is upped by 26% to 1,320p, from 1,050p, reflecting Victrex's strong first half results, which showed growth across all geographies and divisions.However, the broker has scaled back its full year estimates as the second half is a seasonally-weaker period and has been affected by a 2-month plant shutdown (which has added £3m to costs).Panmure Gordon has downgraded its recommendation on business space provider Workspace Group from 'buy' to 'hold', following a strong share price performance of the first half of 2011.While it keeps hold of its forecasts, the broker thinks that the shares are "up with events for now", as the price has risen by around a quarter since the start of January.The target price of 30p is retained.---BC