Two months before Mt. Gox filed for bankruptcy it was sued by a customer seeking the return of funds in a case that highlights some of the red flags raised in the run-up to the collapse of what was once the world's biggest bitcoin exchange, Reuters reported. New York resident Marko Simovic filed a civil action at the Tokyo District Court on Dec. 24, seeking to recover $105,000 he had on deposit at Mt. Gox and about $14,000 in interest, court filings show. Simovic, who described himself as a software developer who previously managed the bitcoin operations for a hedge fund, said Mt.

A federal judge in Chicago froze the U.S. assets of the chief executive of Tokyo-based Mt. Gox as part of a customer lawsuit against the defunct bitcoin trading exchange, The Wall Street Journal reported. Separately, regulators took steps to gain greater control of the fledgling virtual currency and protect consumers from bitcoin scammers.

Japan’s government said Bitcoin isn’t a currency amid calls for its regulation a week after the bankruptcy of Mt. Gox, the Tokyo-based exchange that was once the world’s biggest. There is no law to define Bitcoin and relevant ministries are gathering information on it, Prime Minister Shinzo Abe’s cabinet said in a statement in response to questions from an opposition party lawmaker. Bitcoin transactions can be taxed, according to the statement obtained by Bloomberg News. Japan isn’t the only country grappling with the regulation of Bitcoin.

The Mt. Gox bitcoin exchange in Tokyo filed for bankruptcy protection Friday and its chief executive said 850,000 bitcoins, worth several hundred million dollars, are unaccounted for, The Washington Post reported. The exchange’s CEO Mark Karpeles appeared before Japanese TV news cameras, bowing deeply. He said a weakness in the exchange’s systems was behind a massive loss of the virtual currency involving 750,000 bitcoins from users and 100,000 of the company’s own bitcoins. That would amount to about $425 million at recent prices.

Sony is now looking to sell its former headquarters and surrounding buildings in central Tokyo in its continuing struggle to stem losses from its consumer electronics business, according to a person familiar with the plan, The Wall Street Journal Japan Real Time blog reported. The sale would follow a frenzied unloading of properties in 2013, the most iconic being the $1.1 billion sale of Sony’s U.S. headquarters at 550 Madison Avenue.

The Bank of Japan surprised the market on Tuesday by doubling incentives designed to spur bank lending, weakening the yen and lifting Tokyo stocks at a time when the nation's economy is showing signs of trouble, The Wall Street Journal reported. In the hope that it will open the spigot for lending to the broader economy, the central bank said it will expand two programs where it offers fixed-rate loans at rock-bottom interest rates to commercial banks.

Japan’s huge glacier of stationary household wealth may finally be melting, a development that could help local markets and the country’s economic recovery, The Wall Street Journal Japan Real Time blog reported. After much fanfare, the activation of Nippon Individual Saving Accounts officially kicked off Monday. Part of Prime Minister Shinzo Abe’s economic reform plan, the tax-free NISA system is designed to coax Japan’s chronic savers to put money into stocks, bonds, and other assets to spur domestic growth instead of just parking cash in regular bank accounts.

Japan's financial regulator came down on Mizuho Bank harder than expected yesterday for not addressing loans to members of alleged criminal groups, and for the way it handled disclosures about the problem, the Wall Street Journal reported today. The Financial Services Agency ordered Mizuho Bank to suspend for a month its loan transactions with consumer-credit affiliates, which handled the questionable loans. It also ordered Mizuho Bank and its parent, Mizuho Financial Group Inc., to submit a business-improvement plan by Jan. 17.

In Japan, the world's largest retirement fund is being eyed to help the country come out of its long-running economic woes, the Wall Street Journal reported today. Prime Minister Shinzo Abe and his supporters in the ruling Liberal Democratic Party are trying to push more of $1.2 trillion in public pension money into more speculative investments, especially the stock market. More aggressive investments could help continue the market momentum that has made the Tokyo market the best performer among major markets this year.

Japan needs to quickly lower its corporate tax rate to less than 30 percent to boost the nation’s competitiveness in the global market, Deputy Economy Minister Yasutoshi Nishimura said, according to Bloomberg News today. Prime Minister Shinzo Abe plans to experiment with reforms in the labor market, health care and agriculture and other areas in the zones -- a central plank of his growth strategy. Japan will lower its tax on corporate profits to 35.6 percent from 38 percent in April when a temporary levy to fund reconstruction of regions devastated by the 2011 earthquake and tsunami ends.