MILAN, Sept 17 (Reuters) - The following FTSE 100 companies will go ex-dividend on Thursday, after which investors will no longer qualify for the latest dividend payout. According to Reuters calculations at current market prices, the effect of the resulting adjustment to prices by market-makers would take 0.34 points off the index. COMPANY (RIC) DIVIDEND STOCK IMPACT (pence) OPTION GVC Holdings 16 0.34 Among FTSE 250 companies going ex-dividend are: COMPANY (RIC) Dividend (pence) Crest Nicholson 11.2 Drax Group 5.6 International 3.5 Public Partnerships Limited Petrofac 12.7 (US cents) Playtech 12.1 (EURO cents) Redrow 19 Rank Group 5.3 Renishaw Plc 46 Sanne Group 4.6 Sophos Group 3.5 (US cents) Unite Group 5.2 (Reporting by Danilo Masoni, Editing by Helen Reid)