TOKYO—U.S. private-equity firm Cerberus Capital Management LP has sold a chunk of its stake in Japanese hotel and railway operator Seibu Holdings Inc. worth more than $800 million, according to people familiar with the matter.

Cerberus, one of the first big foreign private-equity firms to enter Japan, has been selling assets in the country in recent years. It frequently clashed with Japanese management teams and its dispute with Seibu came to symbolize a clash of Japanese and Western corporate cultures.

Morgan Stanley MUFG Securities said in a statement Friday that it sold 33.75 million shares, or about a 10% stake in Seibu, that it purchased from a Seibu shareholder Thursday. It declined to name the seller but people familiar with the matter identified it as Cerberus.

The deal would have netted Cerberus about ¥111 billion ($830 million) based on Thursday's closing price of ¥3,300.

Though it remains the top shareholder in Seibu with a 25% stake, Cerberus may sell its remaining holdings in phases, according to market participants.

More than a decade ago, Cerberus invested about ¥100 billion in then-struggling Seibu, whose core unit had been de-listed for falsifying financial statements.

Cerberus had sought to sell part of its stake in Seibu when it relisted in April of last year, but backed out at the last minute because it believed the offering price was too low.

The wait paid off. Shares of Seibu have more than doubled to around ¥3,700 from its debut price of ¥1,600, thanks to solid prospects for transportation and hotel businesses. Seibu's hotel business has benefited from a boom in tourism in Japan, thanks to a weaker currency and an easing of visa restrictions for foreign visitors.

Since Cerberus's investment in 2005, Seibu has made efforts to shed a number of far-flung assets to focus more on core railroad and hotel operations. It was previously highly diversified in the leisure sector, with operations that included golf courses, ski resorts and an amusement park.

In contrast to some Western private-equity funds, Cerberus has been shedding assets in Japan in recent years. In 2013, it sold its entire stake in Japanese lender Aozora Bank Ltd., raising around $1.8 billion. Last year, it agreed to sell its 55% stake in Japanese property operator Kokusai Kogyo Co. to the company's founding family for about $1.37 billion.

Cerberus feuded with Seibu at times. While both Seibu and Cerberus agreed on the goal of a new listing, tensions emerged in 2011 over the timing and the terms. Seibu executives largely cut off contact with Cerberus, saying they wanted to treat all shareholders equally, while Cerberus wanted more say in how the company was run.

The feud went public in March 2013, when Cerberus sought to raise its representation on Seibu's board over the objections of the Japanese company. Cerberus raised its stake to 35% from 32% through a tender offer, allowing more boardroom control. But its proposals at a shareholder meeting in June, including a bid for more board seats, were defeated. Its nominees included former U.S. Vice President Dan Quayle and former U.S. Treasury Secretary John Snow.

Seibu's chief executive said in an interview last year that the firm's relationship with Cerberus had improved since late 2013, when he started talking directly with Cerberus Chief Executive Stephen Feinberg.

Write to Atsuko Fukase at atsuko.fukase@wsj.com

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