Western Digital has offered ¥2 trillion ($17.8 billion) to buy Toshiba's chip unit put up for sale by the embattled Japanese conglomerate, sources said Wednesday.

Western Digital Chief Executive Officer Steve Milligan and Toshiba President Satoshi Tsunakawa held talks Wednesday over the potential acquisition. Toshiba is believed to have expressed reluctance to accept the plan.

According to the sources, Western Digital is planning to put up ¥1.5 trillion through convertible preferred shares, while asking the state-backed turnaround fund Innovation Network Corp. of Japan and the state-owned Development Bank of Japan to provide close to ¥500 billion for common equities.