Siam Cement (SCC) has increased its stake in National Petrochemical (NPC) to 35 per cent, a report in Krungthep Turakij said.  
 
Since the beginning of the year SCC has bought additional NPC shares several times so now it holds 35.03 per cent, up from 24.97 per cent last year. This may delay NPC’s plan to merge with Thai Olefins (TOC) because they have to renegotiate the swap ratio.  
 
Originally, PTT, which holds 38 per cent in NPC and 49 per cent in TOC, intended to merge NPC with TOC by this November.  
 
SCC is aware of the merger plan and has not opposed it.