Broadcom

(BRCM)

was down 19.5% in midafternoon, and other communications chipmakers were also down sharply as concerns about

softening chip demand resurfaced after

Cisco Systems

(CSCO) - Get Report

said it would seek to reduce inventory. Cisco reportedly accounts for 15% of Broadcom's revenue and 10% of the revenue at

PMC-Sierra

(PMCS)

. PMC-Sierra was down 17.3%.