A major Wall Street bank’s vote of confidence for solar power developer SolarCity (SCTY) sent SolarCity stock up more than 9% in Monday morning trading.

Goldman Sachs (GS) upgraded SolarCity stock to a “conviction-buy.” SolarCity stock had previously been given a “neutral” rating by Goldman Sachs. The investment bank also raised its target price for SolarCity stock from $65 a share, to $80 a share, WKRB 13 notes.

SolarCity stock has benefitted from a number of recent upgrades by investment analysts. Equities analysts at Deutsche Bank (DB) and Credit Suisse (CS) have given SolarCity stock solid ratings in recent months.

Since May 2013, SolarCity stock has almost tripled in value.

SolarCity’s gain comes as other solar power stocks also climb. Trina Solar Limited (TSL) shares surged more than 4% in Monday morning trading, while ReneSola (SOL) rose almost 3%.