Aluminium processor Hulamin had cut staff and working hours as it had "considerable exposure" to the industries most severely affected by the global recession, including the automotive sector, it said on Tuesday.
Despite trading being hit by a "sharp" economic slowdown in the second half, sending volume sales down, Hulamin grew profit in the year to December after it had expanded margins.
Chief executive Alan Fourie said that up to 35 percent of aluminium sales went into the vulnerable automotive, construction and transport sectors, with a bias towards exports.
But the balance of sales was in more resilient product areas, such as the soft drink can category.
Can lids made up 25 percent of sales, its biggest line.
Fourie said Hulamin had responded to weaker markets by abandoning its 24/7 production line for now.
The Pietermaritzburg plant closed for two weeks over Christmas and manufacturing was reduced to a five-day week "where appropriate".
Overtime was eliminated in some areas and most contract posts were cut, reducing the 2 600-strong workforce by 150.
Nevertheless, the company said it had a robust model, with returns above the global average.
Higher margins resulting from a successful change in its packaging product mix, cost cuts and a weaker rand would "underpin future earnings".
It predicted sales volumes would continue to fall this year as some customers slashed inventories, making forecasting uncertain.
Orders had become more short term, but there were signs that customers were starting to restock, Fourie said.
Hulamin, which was spun off from Tongaat-Hulett in 2007, said first-half trading had been strong before the global slowdown hit local and export sales.
Volumes fell 6 percent in 2008, but revenue rose 8 percent to R7.1-billion on higher selling prices and a weaker rand. Excluding corporate restructuring costs booked in 2007, operating profit grew 22 percent year on year to R465-million.
Net profit came in at R268-million, up from R41-million after once-off costs of R168-million from a black empowerment deal and the JSE listing in 2007.
A sharp rise in borrowings to pay for an expansion lifted finance costs from R85-million to R118-million. Hulamin has net debt of R1.75-billion, equal to 47 percent of its equity.
Dirk Kotzé, a portfolio manager at Coronation Fund Managers, said Hulamin operated in niche markets, so it had the opportunity to grow market share.
But its forecast of falling volumes spooked the market. The company's high financial gearing made its prospects particularly sensitive to changes in volume, Kotzé noted.
The shares fell 11.15 percent to close at R11.40 on Tuesday.