Shares of IQVIA Holdings Inc. (IQV) tumbled 6.02% in after-hours trading on Monday, following a downgrade from TD Cowen. The sharp decline came after the stock had already underperformed during regular trading hours, shedding 1.19% to close at $213.88.

TD Cowen lowered its rating on IQVIA from Buy to Hold, signaling a shift in their outlook for the healthcare data and analytics company. Despite the downgrade, the firm actually raised its price target for IQVIA from $206 to $215, suggesting a mixed view on the stock's prospects. The market, however, appeared to focus more on the rating change than the increased price target.

The after-hours plunge extends IQVIA's recent struggles, as Monday marked the stock's fourth consecutive day of losses. Before the post-market decline, IQVIA had already closed 5.33% below its 52-week high of $225.91, which it reached on November 7th. The combination of the downgrade and the stock's recent weakness seems to have prompted a significant sell-off among investors, leading to the substantial after-hours decline.