As fears of weakening demand for equipment such as LCD screens that use the LED bulbs, Cree closed down 8.1% to $50.18, Veeco fell 8.3% to $33.44 and Aixtron AG was 5.3% lower at $24.78.

Cree and Veeco share prices are unchanged while Aixtron is down to $24.72 in recent late trading.

Some analysts believed it is related to the combination of poor demand for LEDs and the products that use them, oversupply of the bulbs and a slowdown in the influential Asian LED market for the tumble.
 
Concerns over demand for LEDs have surfaced before, with shares of Veeco, Aixtron and Cree suffering from a similar bout of weakness last month.
 
In addition, according to a report by a Taiwanese newspaper, makers of flat screens were cutting orders to LED makers.