Unusual Machines (UMAC) shares rose by more than 15% in recent trading Monday after the company's chief executive warned shareholders that short sellers might try to manipulate the company's stock price.

CEO Allan Evans said in a letter to shareholders that, among recent company developments, a change of auditors was a "proactive" move and that a recent decision not to do "at-the-market" financing was based on "prioritizing the long-term interests of our shareholders."

"In today's media landscape, it's easy to throw around accusations like 'pump and dump.' While our stock price jumped recently, it was not the result of any marketing campaign initiated or sponsored by us," Evans said.

The letter urged shareholders hold their stake in a cash account, opt out of lending programs, or transfer shares to the company's transfer agent to prevent short sellers from borrowing them for short sales.

Price: 14.80, Change: +2.19, Percent Change: +17.36