Johannesburg - Shares of South Africa's Datatec Ltd tumble 5.4 percent to 48.55 rand after the IT company cuts its full-year outlook for the second time, citing underperformance at its Westcon unit in the United States.

Datatec says it expects headline earnings for the year to end-February to be at least 20 percent below the revised estimate of 40 US cents a share it gave in October.

It had originally forecast headline EPS of 46 cents.

Headline EPS, the main profit measure in South Africa, excludes certain one-time items. - Reuters