** Chemical maker Dow's DOW.N shares rise 2.3% to $34.5 premarket after J.P. Morgan upgrades stock to "overweight" from "neutral"

** Brokerage expects prices of polyethylene, a type of plastic, to rise sharply in near term due to higher energy prices

** A $0.20 increase in ethylene costs is a theoretical benefit to Dow of about $4 bln in EBITDA on an annual basis, says brokerage

** Reasonable for investors to have some exposure to the possibility of an extended disruption to shipping in the Middle East - JP Morgan

** Brokerage increases PT to $40, which represents an 18.6% upside to Dow's last close of $33.72

** Four of 21 brokerages rate the stock "buy" or higher, 16 "hold" and 1 "sell"; their median PT is $29, per LSEG data

** As of last close, Dow shares up 44.2% YTD, having dropped 41.7% in 2025