Methods, systems, and devices for wireless communications are described. In some wireless communications systems, devices (e.g., base stations, user equipment (UEs), etc.) may utilize polar coding along with hybrid automatic repeat request (HARQ) techniques. In these systems, a device may encode bits for transmission by mapping information and parity check bits to a first set of polarized bit channels of a polar code. If this transmission is not successfully received at a decoding device, the encoding device may generate a HARQ retransmission. The device may copy information bits to a second set of polarized bit channels of a second polar code containing the first polar code and may assign parity check bits to the second set of bit channels for the copied information bits. These additional parity check bits for the repeated information bits may increase transmission reliability and may support improved early termination at the decoding device.