Marvell Technology Inc. (MRVL) just agreed to the biggest deal in its history. Shareholders are answering with the stock's worst sell-off in a generation.

Shares fell 7.4% to about $182 on Monday, extending a three-day slide to 27.7%. That puts Marvell on track for its steepest three-session drop since Sept. 27, 2001, deeper than the 27.2% plunge of March 2025.

The selling began Oct. 29, after reports surfaced that Marvell was in talks to buy Lumentum Holdings Inc. (LITE). On Monday, the company confirmed an all-stock deal valuing the laser maker at $115 billion.

Lumentum holders will receive 4.5 Marvell shares each and own about a third of the combined company. As a result, existing investors face heavy dilution. Roughly $61 billion of Marvell's market value has vanished since Oct. 28.

Meanwhile, the VanEck Semiconductor ETF (SMH) edged up 0.2%.