Speciality retailer Supercheap Auto is battling a downturn in the automotive category forcing it into deep discounts and punishing the profits of its parent, ASX-listed Super Retail Group.

While group sales rose 4 per cent to $2.1 billion over the first half – and same-store sales were up 1.8 per cent – net profit was 9 per cent lower to $130 million, below market forecasts. The stock tumbled nearly 14 per cent to $14.01.