Shares of the Cincinnati company at last check dropped 9.2% to $8.75. The stock dropped toward a more than 10-month low. It was near $43 in early February.
Workhorse reported a net loss of $120.5 million compared with a profit of $4.8 million in the year-earlier quarter.
Revenue rose sixfold to $521,060 from $84,300 in the year-ago quarter, but the latest figure came in below the FactSet consensus analyst estimate of $2.3 million.
The sales increase was related primarily to more trucks delivered: Workhorse delivered six in the first quarter.
Excluding noncash adjustments, the Q1 operating loss was $16.5 million against $9.1 million a year earlier.
"We have had a step function improvement in production in the last month," Chief Executive Duane Hughes said in a statement.
"Although we had planned to have achieved our year-to-date number of trucks produced sooner, we took the additional time to ensure that we were building top-quality vehicles for our customers while improving our production processes.”
Hughes added that bottlenecks within the global supply chain and offshore shipping delays of commodity raw materials and components, as well as Workhorse's initial stages of production, limited the company's capacity to produce during the first quarter.
"However, our vehicle production numbers in April in comparison to the last few quarters are encouraging as are the proactive steps we are taking to build our volumes and ensure consistent production," Hughes said.
"Though we are certainly making steady progress in improving our vehicle manufacturing throughput, we are adjusting our 2021 production estimate to 1,000 units.
"Our deliberate approach to growth will ensure we are well-positioned to deliver the increased volumes we expect in 2022 and beyond," said Hughes.