Shares of Castex Technologies may remain in focus following its troubled promoter Amtek Auto pledging more shares of the company. In an exchange disclosure, it said Amtek Auto had pledged 60.50 lakh shares with State Bank of Bikaner & Jaipur on September 28. With this, pledged shares increased to 21.56 per cent of the paid-up capital of the company from 19.96 per cent. Amtek Auto has been struggling to meet its commitment on bonds.