Shares dipped to $119 from yesterday's close of $133, but have rebounded slightly to trade near $121, a 9-percent decline from yesterday.
Earlier this morning, Cummins reported that third-quarter profit was up 7.6 percent over last year, to $184 million, fueled by a 20-percent increase in sales.
Still, the $1.69 in earnings per share was short of the $1.95 anticipated by analysts surveyed by Thomson Financial.
Cummins said its share of the North American heavy-truck market rose to 36 percent from 27 percent at the end of last year as engine manufacturers complied with new emissions standards. The increase came amid a drop in orders, since shippers had stocked up on trucks in advance of the switch to contain costs.
Cummins' power generation and distribution businesses achieved record sales, and its business that includes filters and turbochargers, among other components, experienced an increase in sales as well.
"Our technology leadership has resulted in a sustainable competitive advantage for Cummins, and we remain focused on producing profitable growth for all our stakeholders," said Cummins Chairman and CEO Tim Solso.
Cummins isn't accustomed to seeing its stock fall. The shares have been on a tear, rising tenfold since 2003.