(Reuters) – Hyzon Motors received a subpoena (US Securities and Exchange Commission, SEC) on Wednesday. The hydrogen-fuel-cell truck manufacturer disclosed this in a regulatory filing. This sent its shares down almost 13% prior to the bell.

SEC asked company for documents regarding the allegations in Blue Orca Capital’s report.

Blue Orca disclosed in September a small position in Hyzon. It claimed that Shanghai HongYun, the largest truck manufacturer customer was “fake” and was created days before an announcement about a contract to supply 500 fuel cell vehicles.

Hyzon, which rejected the report in October, stated that its chief executive officer had not recorded the meeting of short sellers with management. He requested “any information or clarifications” and “to verify its claims.”

Hyzon indicated Wednesday that it would cooperate with the SEC during the investigation.

Blue Orca as well as the SEC weren’t immediately available for comment.

Hyzon, which designs a hydrogen-powered truck specifically for its customers, called SuperH2Truck in July 2021 by merging with a firm that is still a check company.

Premarket trading saw a 9% drop in shares, but the company recovered its losses.