** J.P.Morgan raises stock rating on building material
supplier Martin Marietta Materials MLM.N to "overweight" from
"neutral"
** "We believe MLM has attractive geographic exposure, with
operations in states that could continue to outperform the
country's national average and that have attractive midterm
growth potential" - brokerage
** Also raises target price to $640 from $515, representing
a 7.2% upside to stock's last close
** Says MLM has solid exposure to the cement industry in
Texas, which is a high-growth market but also very competitive
** Up to last close, stock was up 19.65% YTD
(Reporting by Anshuman Tripathy)
((Anshuman.Tripathy@thomsonreuters.com))