** Chipmaker Marvell Technology's MRVL.O shares rise 4.8% to $119.82 premarket

** Barclays upgrades MRVL from "equal weight" to "overweight" and raises its price target from $105 to $150, which implies 31% upside from stock's last close

** Brokerage cites strong growth in co's optical networking business driven by AI data center buildouts

** Marvell is first and foremost an optical company, Barclays says

** "Industry checks suggest optical ports should double in 2026 and double again in 2027. Our math implies that Optical could grow ~90% for MRVL this year and next."

** 37 of 44 brokerages rate the stock "buy" or higher, seven "hold"; their median PT is $120

** Up to Wednesday's close, stock had risen about 35% YTD compared with a 20.2% increase in the Philadelphia SE Semiconductor index .SOX