Global business

After years of delay and an often tetchy debate between Wall Street and America's regulators, the "Volcker rule" at last came into effect. Named after Paul Volcker, a former chairman of the Federal Reserve, the rule stops big banks from engaging in certain kinds of risky speculative bets, activities that produced handsome profits for some before the financial crash. Most banks have cut back their investment activities to take account of the rule.

The Federal Reserve finalized its new requirements for the amount of additional capital that America's "most systemically important" banks will have to hold to protect against losses. JPMorgan Chase had its minimum capital requirement raised by 4.5 percent of assets, more than any of the seven other banks that the regulation applies to.

Gold prices dropped to a five-year low of around $1,090 per troy ounce, partly in reaction to the Fed repeating that it is on course to raise interest rates this year. The news that China's central bank, which wants to boost the yuan as a trading currency, had made much smaller purchases of gold reserves than had been thought was also a factor.

Lockheed Martin agreed to buy Sikorsky, which makes the Black Hawk helicopter for the American army, from United Technologies in a $9 billion deal. It is Lockheed's biggest acquisition since 1996.

Sony announced plans to start a new business using drones for a variety of services. The announcement came a few days after the first government-approved delivery by drone, of medicine to a clinic in Virginia, took place in the U.S. But the pace at which the technology is being adopted by unregulated hobbyists is worrying some.

An independent committee found that Toshiba had overstated profits by $1.2 billion over seven years, in one of the biggest accounting scandals to hit Japan's corporate world in years. Hisao Tanaka stepped down as chief executive of the electronics and nuclear-power group after the panel's report described the problems as "systemic." Half of the board's 16 members also resigned.

Maurice Obstfeld was appointed the IMF's new chief economist. He will succeed Olivier Blanchard in September. Born in New York, Obstfeld is a professor at the University of California, Berkeley, and sits on President Obama's Council of Economic Advisers.

The British government told Martin Wheatley it would not renew his contract as head of the Financial Conduct Authority. Wheatley said he was disappointed, as he had "unfinished business" still to do. The FCA has taken a tough approach toward wrongdoing in the city, but with the scandals in banking receding, the government is now hinting at a lighter regulatory touch.

The European Commission ruled that a tax break granted to Électricité de France by the French government in 1997 was illegal and ordered it to repay $1.5 billion. The case was reopened two years after Europe's top court criticized an earlier investigation by the commission.

Political economy

Prosecutors opened an investigation into allegations that Brazil's former president, Luiz Inácio Lula da Silva, improperly lobbied foreign leaders, including Cuba's, to award contracts to Odebrecht, a construction company.

Saudi Arabia launched a big crackdown on militants, announcing that it has arrested 431 people it suspects of being connected to Islamic State in Iraq and the Levant.

Amid widespread criticism across Africa and in the West, President Pierre Nkurunziza of Burundi looked certain to be elected for a third term, despite the constitution's two-term limit and street protests in the past three months that have left scores of people dead.

At least 32 young aid volunteers in Turkey were killed by a suicide bomb in the town of Suruc near the border with Syria, which was blamed on ISIL. In the adjacent part of Syria, ISIL and Kurdish forces have been battling for control of several strategic towns. The bomb triggered protests against President Recep Tayyip Erdogan, who is accused of being fainthearted in the fight against ISIL. Kurdish militants killed two Turkish policemen in revenge.

Thousands of supporters of a right-wing nationalist group, Right Sector, demonstrated against the government in Kiev, the capital of Ukraine. Earlier this month there were armed clashes between Right Sector and local authorities in a region of southwestern Ukraine bordering Hungary and Slovakia.

Mitsubishi Materials, an affiliate of the Mitsubishi group, became the first Japanese firm formally to say sorry for treating American prisoners as forced labor during the second world war. On Aug. 15, the 70th anniversary of Japan's surrender, Shinzo Abe, the prime minister, is expected to make a statement that addresses lingering resentments over the war.

In China, Ai Weiwei, perhaps the country's best-known artist, who was detained in 2011 and has been barred from traveling since, was given his passport back. A show of his work at London's Royal Academy opens in September, and he now hopes to visit it.