What happened Shares of residential and commercial solar company SunPower (NASDAQ: SPWR) dropped Thursday after the company reported its fourth-quarter and full-year 2020 earnings last night. As of 2:45 p.m. EST, shares were 15% below Wednesday's closing price. So what Though SunPower beat the expected $0.11 per-share income by $0.03, according to FactSet, revenue of $342 million for Q4r ended Jan. 3, 2021 missed estimates. Investors today appear to be unhappy with the first-quarter and full-year 2021 guidance the company provided. Image source: Getty Images. Now what Though SunPower said it expects to lose between $10 million and $20 million in the 2021 first quarter, the company expressed confidence that its full-year 2021 results will meet or exceed previous guidance, which predicted revenue growth of about 35% in 2021. But investor expectations have also been raised recently. An acceleration of solar-power adoption in the U.S. has been predicted with the new Democratic administration. This includes growth in solar-storage solutions in which SunPower also participates. In the company's own words as stated in the earnings release: "Given strong industry tailwinds, continued federal policy support as well [as] increased demand for its residential and commercial storage solutions," it expects strong future growth to continue. But shares of SunPower have risen almost 600% in the past year, which raises growth expectations to justify its valuation. Investors today appear to be adjusting to the reality of a time frame for that growth. For long-term investors, the dip may be a buying opportunity -- if one is comfortable with the volatility of the sector. 10 stocks we like better than SunPowerWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and SunPower wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of November 20, 2020 Howard Smith has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.Source