TOKYO — Toshiba, the huge but struggling Japanese conglomerate, traded some of its size for financial security on Thursday by selling off most of its profitable microchip business.

It was not the way the company, which has long been accused of being bloated and directionless, had hoped to slim down.

Toshiba said it had signed a deal to sell 60 percent of the microchip unit, Toshiba Memory Corp., to a group of international investors that includes Bain Capital and Apple. The deal, which followed months of tumultuous negotiations, will net Toshiba about $14 billion.

Toshiba has staked its future on the sale, with the proceeds earmarked to help repair the financial damage from a disastrous foray into nuclear power in the United States. The episode threatened to bankrupt the company, one of Japan’s biggest and proudest.

In an era when the global technology industry is dominated by nimble specialists selling cutting-edge design and software, Toshiba has been defined by a stultifying management hierarchy, a dogged focus on hardware, and a scattered portfolio of businesses.

“Toshiba is one of Japan’s last zombies,’’ said Jesper Koll, chief executive of WisdomTree Japan, an investment firm. “It’s the last of the big conglomerates that does not have a defined strategy.’’

Similar problems have hampered other Japanese groups, but Koll said Toshiba had been particularly slow to address them. Others, like Hitachi, another refrigerators-to-power-plants conglomerate, he said, “made hard decisions’’ to restructure and become more accountable to shareholders, while Toshiba delayed.

Then came an accounting scandal in 2015, in which Toshiba admitted overstating its earnings by $1.2 billion over seven years. Top company leaders resigned, and investigators hired by the company blamed “a corporate culture where it is impossible to go against one’s bosses’ wishes.’’

Toshiba had been covering up cost overruns at its US nuclear subsidiary, Westinghouse Electric, which it bought amid an ill-timed expansion in 2006. Those losses later ballooned: Westinghouse sought bankruptcy protection in March, after costing Toshiba $6 billion in write-offs. Toshiba said it would stop building new nuclear power plants and focus on maintaining older ones.

Now, with the sale of a majority of the microchip unit, Toshiba is shrinking further.

The company had been negotiating the sale for months, with a shifting roster of potential investors. The final list of buyers, disclosed in a statement Thursday, had some surprising omissions.

Two financial institutions controlled by the Japanese government that Toshiba had previously identified as major potential investors will not contribute money initially, the company said. The institutions, Innovation Network Corp. of Japan and the Development Bank of Japan, may invest later.

The investors were instead drawn from the private sector. In addition to Apple, they include US businesses Seagate Technology and Kingston Technology, two data-storage companies, and a venture capital arm of Dell, the computer maker. The South Korean semiconductor maker SK Hynix and Hoya, a Japanese manufacturer of optical equipment, were also named as investors.

Toshiba will retain just over 40 percent of the unit, one of the world’s largest producers of the flash memory chips used to store data in smartphones and other digital devices. In negotiating the deal, Toshiba struggled to balance its need for cash and its desire to retain control of the microchip unit, which has been described as the crown jewel in its vast portfolio of businesses.

Toshiba pioneered its core technology, NAND flash memory, and although it has fallen to second in global production, behind Samsung Electronics of South Korea, the business has generated the largest share of Toshiba’s profits in recent years. Among the company’s concerns was that its technology could fall into the hands of investors, like SK Hynix and Kingston, that are also competitors.

Japan dominated chip making in the 1980s and 1990s but has lost ground. Tsugio Makimoto, a retired Hitachi engineer, said conglomerates were once good at nurturing chip businesses, because they had money for research and factories. But as change quickens, “management speed and specialization are more important.’’