Vicor's stock plunged 5.01% in pre-market trading on Friday.
The decline is attributed to profit-taking activity following a substantial post-earnings rally. The company's strong FY26Q1 results had previously exceeded market expectations, fueling significant short-term price gains that prompted investors to lock in profits.
Additional downward pressure came from recent insider selling, with company directors reducing their holdings. This activity intensified market concerns about near-term selling supply and contributed to the stock's volatility.