Wall Street is on track for solid weekly gains — and certain stocks stood out from the rest. The S & P 500 is up 1.6% week to date, on pace to snap a three-week decline. The Dow Jones Industrial Average and Nasdaq Composite are up 1.5% and 2.3%, respectively. These gains come as investors became more optimistic about the Federal Reserve's path on interest rate hikes. Atlanta Fed President Raphael Bostic said this week that he believes the central bank can keep its interest rate hikes to 25 basis points, rather than a half-point increase favored by more hawkish officials. Take a look at some of this week's biggest gainers, and analysts' expectations for them going forward. Solar energy names First Solar and SolarEdge Technologies both made the list of this week's biggest gainers. First Solar was this week's top performer, with shares popping 23.2% following strong guidance for 2023. The energy company is poised to benefit from the Inflation Reduction Act's manufacturing tax credits , according to UBS, which upgraded the stock to buy from neutral. More than half of analysts covering the stock rate it a buy, but also see it coming down slightly from current levels. Shares are up 41% this year, continuing to rally after soaring 71.9% in 2022. SolarEdge, meanwhile, popped 9% for the week through early Friday trading. Nearly two-thirds of analysts covering the stock rate it a buy. The average price target on SolarEdge implies upside of nearly 14%. Software company Salesforce was also one of this week's notable gainers, with the stock on Thursday having their best day since 2020 following a blowout earnings report. Shares were up 16.7% for the week as of early Friday, and up almost 40% since the start of the year. Salesforce is well-liked by analysts, with 68% of those covering the stock giving it a buy rating. The average analyst price target also implies upside of roughly 15%. "We continue to see the valuation framework for Salesforce shifting to FCF/share, and view management's focus toward a much more aggressive profitability glidepath over the long-term highly favorably," JPMorgan analyst Mark Murphy said in a note this week . Railroad operator Union Pacific Corporation also made the list. Shares rose 9.1% after the company announced a CEO change later this year. Bank of America upgraded shares to buy from neutral following the announcement. Several non-energy materials stocks were also strong performers this week, with Steel Dynamics and Mosaic gaining 12.5% and 9.4%, respectively.