March 4 (SeeNews) - Croatia's Hrvatski Telekom [ZSE:HT-R-A] said it has extended to March 18 from March 2 the deadline in a tender for the sale of its 17.41% stake and the 36.90% stake held by Zagrebacka Banka [ZSE:ZABA] in Optima Telekom [ZSE:OPTE-R-A].