South African retailer Shoprite has reported a jump in half-year earnings after increasing its sales and market share.

The company said its headline earnings per share – a key metric in South Africa – increased 18.6% to 280 cents in the six months to the end of December. Net profit leapt 73.3% to ZAR1.72bn. Trading profit increased 16.7% to ZAR2.16bn.

The improved profits came as sales rose 13.2% to ZAR41.05bn. Revenue grew domestically and outside South Africa, although Shoprite noted the weakness of the rand helped its sales growth in other markets.

Shoprite booked an exchange rate gain of ZAR27.7m, compared to losses of ZAR13.4m a year earlier. The retailer said the change in currency meant South African products were “more competitive” but it added the cost of operating outside its domestic market became more expensive.