$ArcLight Clean Transition Corp(ACTC)$Proterra in January agreed to go public through a merger with ArcLight Clean Transition Corp in a deal valued at $1.6 billion, including debt.The company is going public through a merger with a blank-check company or special purpose acquisition company (SPAC). SPACs are shell companies which raise money through an IPO of its shares to take another company public within two years.The transaction is expected to close in the first half of 2021.