The planned listing will end a prolonged hiatus in initial public offerings (IPO) on Spain's main market since renewables company Opdenergy's lackluster debut in July.

EiDF Solar, which installs solar panels, currently trades on the junior market of the BME Exchange and plans to relist its shares on the senior stock market, known as Mercado Continuo.

Founded in 2008, EiDF debuted on BME Growth, a trading venue for start-up companies, in 2021. Last year, it announced plans to move its listing, hiring Lazard to line up underwriters for the float.

Banks were recently appointed after being invited to pitch for a role in the deal, the sources said.

Bank of America, Santander and Societe Generale declined to comment. EiDF did not immediately respond to a request for comment.

The group must place more shares with investors to meet a 25% minimum free-float requirement for the country's main market.

About 15% of the stock is currently held by public equity investors, with chief executive Fernando Romero holding a majority stake, as per its latest quarterly report.

Shares in EiDF, one of the most actively traded stocks on BME Growth, have rocketed since its stock market debut in 2021.

They closed on Tuesday at 28.44 euros, up from the 4.20 euros paid by investors in its initial float, implying a market capitalisation of roughly 1.6 billion euros ($1.71 billion).

Based in northwestern Spain, the company started out installing solar panels for other businesses but now develops its own solar farms as well.

It posted third-quarter 2022 revenues of 315.54 million euros, up from 30.55 million euros the previous year, and earnings before interest, tax, depreciation and amortisation (EBITDA) of 46.86 million euros, up from 7.10 million euros.

Europe's IPO activity almost ground to a halt last year amid soaring interest rates and Russia's invasion of Ukraine, but there are signs that companies are again considering going public.

Earlier this month, German web hosting services provider IONOS and Italian industrials firm EuroGroup Laminations listed part of their shares on their home countries' stock markets, with mixed results in the aftermarket.

Spanish construction materials company Cosentino is working with JPMorgan and Goldman Sachs to list its shares on the stock market in 2023, according to two sources close to the Cosentino IPO.

($1 = 0.9331 euros)

(Reporting by Pablo Mayo Cerqueiro and Andres Gonzalez; editing by Dhara Ranasinghe and Jane Merriman)

By Pablo Mayo Cerqueiro and Andres Gonzalez