Seagate Technology and Western Digital shares fell on Tuesday as investors assessed Toshiba's potential expansion in the hard-disk drive market and a reported bidding contest for TDK's magnetic-heads business. Bloomberg reported that Seagate and Toshiba are competing to acquire the hard-drive magnetic-heads unit of TDK, the only independent manufacturer of magnetic-recording heads.

Toshiba's plan to build more hard disk drives is landing on its two U.S.-listed rivals and not hurting the memory chip stocks around them. Western Digital (NASDAQ:WDC | WDC Price Prediction) stock is down 6% to $414.

The AI boom has created an unexpected comeback story for one of technology's oldest products: the hard drive. But as demand for high-capacity storage surges, the three companies still making hard disk drives (HDDs) — Seagate Technology Holdings PLC (NASDAQ:STX), Western Digital Corp (NASDAQ:WDC) and Toshiba — are moving in very different directions.

Central Pacific Bank Trust Division boosted its holdings in Seagate Technology Holdings PLC (NASDAQ: STX) by 111.7% during the third quarter, according to the company in its most recent filing with the Securities and Exchange Commission. The fund owned 2,380 shares of the data storage provider's stock after buying an additional 1,256 shares

Seagate stock was edging down following a report it is competing with Toshiba over a crucial acquisition in the hard-disk drive space.

Shares of Western Digital WDC and Seagate Technology rebounded on Monday as analysts assessed the potential impact of Toshiba's plans to expand hard disk drive (HDD) production. Western Digital shares rose 6.8% in Monday afternoon trading, while Seagate gained 5.9%.

Seagate just shed billions in market cap on a single Toshiba headline, yet its nearline drives are locked into contracts stretching deep into 2027.

Even if Toshiba doubles its capacity, analysts say it has a ways to go to catch up with Western Digital and Seagate

Eastern Bank boosted its stake in Seagate Technology Holdings PLC (NASDAQ: STX) by 5.5% during the third quarter, according to its most recent filing with the Securities and Exchange Commission (SEC). The firm owned 73,812 shares of the data storage provider's stock after purchasing an additional 3,880 shares during the period. Seagate Technology

Last week's drop is good news for investors wanting to get in, analysts say.