Western Digital Corp. is making a forceful case for its bid to take control of Toshiba Corp.'s memory-chip business amid a fierce bidding war.

The San Jose, California-based company is in talks with state-backed investment funds Innovation Network Corp. of Japan and Development Bank of Japan Inc. about options for a bid, said Mark Long, Western Digital's chief financial officer, during an interview in Tokyo. Long also suggested his company has held discussions with Apple Inc.

Western Digital became Toshiba's manufacturing partner in the flash-memory business when it acquired SanDisk Corp. for $15.8 billion last year. That investment is now under threat after Toshiba narrowed the list of contenders to a group that includes Western Digital's rivals, including Taiwan's Hon Hai Precision Industry Co., South Korea's SK Hynix Inc. and chipmaker Broadcom Ltd. Toshiba should negotiate with Western Digital first, Long said.