Shares of Lordstown Motors, a start-up aiming to make electric pickup trucks, dropped 13 percent in premarket trading on Tuesday after the company said that it would “at best” make just 50 percent of the vehicles it had previously hoped to this year, unless it is able to raise additional capital.

“What we are saying is that if we don’t get any funding, we might only make half of what we thought,” Lordstown’s chief executive, Steve Burns, said Monday during a conference call.

Mr. Burns said the company was still on track to begin making trucks by September.

Lordstown has had discussions with some strategic investors who could pump money into the company, he said, and it has looked into borrowing money by using its plant or other assets as collateral.

He also said the company was looking into borrowing from a federal government program meant to support the development of electric vehicles, but it was unclear if it had any funds left.

Lordstown would be able to make as many as 2,200 trucks by the end of the year if it gets funding, Mr. Burns said. Without additional capital, it would probably make fewer than 1,000.

Mr. Burns has been hoping Lordstown would be the first to produce an electric pickup truck aimed at commercial fleets such as large construction and mining companies, but it will soon face some formidable competition. Ford Motor last week unveiled an electric version of its F-150 pickup that is supposed to go on sale next spring.

Lordstown gained attention because it bought an auto plant in Lordstown, Ohio, that General Motors had closed. It was also once hailed by former President Donald J. Trump for saving manufacturing jobs.

It became a publicly traded company last year by merging with a special purpose acquisition vehicle, a company set up with cash from investors and a stock listing. Several other electric vehicle and related businesses have gone public through similar mergers in recent months, taking advantage of investors’ desire to find the next Tesla.

Lordstown, which is being investigated by the Securities and Exchange Commission, said it lost $125 million in the first quarter of 2021, but ended the period with $587 million in cash.