* Q3 EPS $0.24 vs analysts expectation for $0.24
* Sees Q4 gross profit margin about same as Q3 2010
* Shares down 4.5 pct
DETROIT, Oct 21 (Reuters) - Auto parts maker Gentex Corp (GNTX.O) said quarterly profit jumped over 43 percent, but tight supplies of some electronic components would keep pressure on gross profit margins.
Shares fell 4.5 percent.
Gentex, which makes automatic dimming rearview mirrors and other components, said its gross profit margin fell 1 percentage point in the third quarter from the second quarter, to 35.7 percent.
Cost increases from supply chain stress are expected to continue for several quarters and gross profit margin in the fourth quarter will be about the same as the third quarter, Gentex said. It did not identify the components.
Net income rose to $34.3 million, or 24 cents per share, in the third quarter, from $23.9 million, or 17 cents per share, a year earlier. Revenue rose 33 percent to $206.8 million.
Analysts on average had expected Gentex to report earnings of 24 cents per share, according to Thomson Reuters I/B/E/S. Analysts expected revenue of $204.7 million.
Shares of Gentex, which expects revenue to increase 20 percent in the fourth quarter from a year before, were down 98 cents, or 4.5 percent, at $20.60 Thursday on the Nasdaq. (Reporting by David Bailey, editing by Gerald E. McCormick)