Company history

Nippon Miniature Bearing was founded in July 1951 in Itabashi, Tokyo, with capital of $2,778 (¥1m) — Japan’s first company devoted entirely to miniature bearings. The idea came from wartime discovery that the instruments of American B-29s ran on them; localising their production was as much a question of industrial self-sufficiency as of business. It proved harder than the founders expected. Races, balls and retainers all demanded tolerances no one in Japan yet knew how to hold in volume, and within a year of founding the company was out of cash.

Banks would not lend to an unproven precision-parts maker. Ayukawa Yoshisuke, founder of the Nissan zaibatsu, instead asked a customer of the firm, Takahashi Seiichiro, to take the rebuild on. Takahashi put in $5,556 (¥2m) in 1952, became the largest shareholder, and went on pouring his own money in; in 1959 he brought his eldest son, Takahashi Takami, over from Kanebo. Being saved by one man’s purse rather than by a bank left a company that decided from the top, moved quickly, and financed itself outside the banking system — the habit that would define it for decades.

The factories moved out of the city: Kawaguchi in 1956, a new Karuizawa plant in 1963, and by 1965 everything consolidated at Karuizawa with the head office at Miyota, Nagano — cheap land and available labour, chosen early. By 1963 Minebea held roughly 70% of the Japanese miniature-bearing market, won by carrying 500 varieties in stock so that instrument, electronics, office-machine and appliance makers could all take small lots at short notice from the same plant. It listed on the second section of the Tokyo Stock Exchange in 1961 and moved to the first in 1970. Abroad it built sales and production almost at once: a tie-up with MPB, the largest American miniature-bearing maker, in 1959; a US subsidiary in 1968, when exports already ran near 70% of sales; a British sales company in April 1971; and in September 1971 the purchase of SKF’s REED plant, its first factory in America. Takahashi Takami, president from 1966 at the age of 38, kept nearly everything in-house — “about all Minebea buys outside is bar stock and balls; we are the only bearing maker that makes its own retainers,” he said — and that vertical integration is what would later make offshore production pay.

Takahashi Takami did not believe his products sold because they were good. “The currency relationship is the biggest single reason our products sell — not superior technology or productivity,” he said. If the yen was going to rise, exporting from Japan would lose on price no matter how well the plants ran, so the answer was to get ahead of the exchange rate and put the work where wages were low. When the Nixon shock pushed the yen up, he moved production to Singapore in 1972. Japanese banks judged the company too weak to finance it and refused; he raised the money for the plant on foreign bond markets, in Switzerland and elsewhere. “There was no calculation involved. There was simply no way to live except abroad.” He was equally blunt about the cost at home, saying that 60% of Karuizawa’s equipment would go to Singapore and the plant would be left hollow.

Thailand followed in 1980, with plants in Ayutthaya and other provincial sites: the newest machinery, production lines 250 metres long finishing at the far end, and a fifth of the whole operation assigned to inspection. Karuizawa became a mother plant training Thai staff. The two-layer structure — local wage costs, Japanese quality management — became the template. By 1988 some 99% of bearing output was offshore, and the business press rated Minebea the most yen-proof manufacturer in Japan.

The same appetite ran through the domestic business. In October 1981 the company absorbed four affiliated makers — screws, communications equipment, ordnance, wheels — and renamed itself Minebea Co., Ltd., a components conglomerate rather than a bearing house. In 1984 it secured a 350,000-square-metre site at Tateyama, Chiba, and put $126.3M (¥30bn) into semiconductors, starting 256K DRAM production in 1986 on the theory that a chip line was merely an equipment business: “making 256K is not that hard — licence the base technology, line up the newest machines, add the precision skills from miniature bearings. It is the same as a spinning mill a generation ago. Even Southeast Asia could do it.” In 1985 it launched a hostile tender offer for Sankyo Seiki, almost unheard of in Japan then, and lost; at the same time it was itself nearly taken over by foreign investors. Yields were poor, DRAM never became a pillar, and the belief that bearing know-how would transfer to a miniaturisation race proved wrong. Bearings and motors, by contrast, kept compounding through acquisition — New Hampshire Ball Bearings in 1985, Rose Bearings in Britain in 1988, a disc-motor venture with Papst in Germany in 1990. Takahashi Takami died suddenly in 1989, and the top-down era ended with him.

The currency hedge worked; growth did not follow. From about 1987 Minebea pushed into electronic components — keyboards, printer parts — and by the late 1990s that low-margin business accounted for roughly three-quarters of sales while the high-share bearing operation supplied the profit. Consolidated revenue was $2.2B (¥279bn) in the year to March 2002 and $2.7B (¥256bn) in the year to March 2009: for nearly two decades the company could not break through a ceiling around ¥300 billion. President Hagino Goro insisted in 1999 that “building on bearings was not a mistake,” but no second pillar appeared. With Takahashi gone, the speed of top-down decision went with him, and neither DRAM nor hostile M&A had left anything that earned.

The one structural move of the period was in motors. In April 2004 Minebea formed a joint venture with Matsushita Electric’s motor company, pooling four information-motor lines — fan, stepping, vibration and brushed DC — and in 2010 it bought Panasonic out and absorbed the business outright. Even so the group still lived on bearings, and after the financial crisis operating profit fell to $143.3M (¥13bn) in the year to March 2009. The stagnation is what created the mandate for a different kind of leadership.

Kainuma Yoshihisa, a lawyer by training who had studied in the United States, took the presidency in 2008 and inverted the 1980s formula. Instead of one enormous bet outside the core, he kept bearings at the centre and bought small businesses next to it, continuously, so that no single failure could sink the plan: the German specialist myonic in dental, medical and aerospace bearings in 2009; the Matsushita motor venture taken over in full in 2010, along with a mould maker and a Chinese LED-backlight plant at Suzhou; the Korean small-motor maker Moatech, an aircraft-parts maker and Swiss Paradox Engineering in 2013; Sartorius Mechatronics in 2015. Smartphone demand made the backlight business scale in China and Thailand. Kainuma credited Thailand’s stability to three decades of accumulated employment there — through the Asian financial crisis Minebea declined to cut staff, and the retention that produced now runs to second-generation employees.

The turning point came in 2016, when Minebea agreed to integrate with Mitsumi Electric. The share exchange completed in January 2017 at an acquisition cost of $509.9M (¥56bn) — cheap, because Mitsumi had just posted a net loss of $88.2M (¥10bn) on smartphone camera actuators — and the company renamed itself Minebea Mitsumi, keeping the other side’s name in its own. Revenue went from $5.7B (¥639bn) in the year to March 2017 to $8.0B (¥881bn) the year after. Kainuma’s reasoning was mechanical rather than financial: a high-performance motor needs good bearings and power semiconductors, so the more of the set you make yourself, the better the whole can be optimised. He called it aigō — combination — and likened the group to Uniqlo, which makes its fleece, underwear, trousers and socks itself: not a conglomerate of independent units but eight businesses stacked vertically. He also claimed to decide an acquisition in three seconds.

The roll-up then ran through the adjacent industries, mostly by taking in companies that had run out of financial room. U-Shin, an automotive access maker with $1.3B (¥149bn) of sales but $383.2M (¥42bn) of interest-bearing debt and no capacity to invest, was acquired by tender offer in 2019 for about $227.5M (¥25bn), putting Minebea Mitsumi into door handles, locks and keys and into direct dealing with carmakers for the first time. Ablic in analog semiconductors followed in 2020, MMI Semiconductor from Omron in 2021, Honda Lock in 2023, and Hitachi’s power-device business in 2024 for $270M (¥41bn). Revenue more than doubled, to $10.2B (¥1.52tn) in the year to March 2025. Then, in 2025, the method met its opposite: Taiwan’s Yageo bid for Shibaura Electronics, a profitable thermistor maker, and Minebea Mitsumi entered as white knight at the target’s request. It was the first time it had contested a healthy specialist rather than absorbing a distressed one cheaply. It raised its cap to $41 (¥6,200) a share, refused to go further, and let the tender lapse in September.