Business this week

Chuck Prince resigned as Citigroup's chairman and chief executive after America's biggest bank announced additional write-downs of up to $11 billion stemming from subprime mortgages. Robert Rubin, a former treasury secretary, was named as Citi's new chairman. Investors, already jittery at the departure of Mr Prince, were rattled further when Morgan Stanley said it had lost $3.7 billion on investments linked to subprime-mortgage debt. AIG, the world's biggest insurance company, saw its quarterly net profit drop by 27% compared with a year ago, and booked write-downs on mortgage-related assets.

General Motors reported a $39 billion net loss for the third quarter, mainly because of a write-down of deferred tax credits. “Ongoing challenges” in America's mortgage market also hurt its financial-services unit. Without the charge, GM made an adjusted net loss of $1.6 billion. Its share price slid.

Ford reached a tentative agreement on a new contract with the United Auto Workers, the last of Detroit's big three carmakers to do so. Ford is expected to make further job cuts once the document has been ratified by UAW members, which could take several weeks. Chrysler said on November 1st that it would shed up to 10,000 jobs after confirmation that workers there had voted to support their new contract.

BHP Billiton confirmed it had made a takeover approach to Rio Tinto, its smaller rival, but had been rebuffed. Rumoured for months, a merger would create a mining behemoth.

How much is it really worth?

PetroChina's share price soared on Shanghai's feverish stockmarket following the offering of just over 2% of its shares there (it is also listed in Hong Kong and New York). Much was made of the notion that on the basis of its Shanghai share price PetroChina had become the world's most valuable company: at one point it was worth $1 trillion—equal to Exxon Mobil, Shell and BP combined.

PetroChina wasn't the only Chinese company to surpass stockmarket expectations. Alibaba, an internet company, saw its share price almost triple following its initial public offering in Hong Kong.

Wireless Android

Google took the wraps off its long-awaited strategy to enter the mobile-phone industry. Termed “Android”, Google's plan is based around software that makes the development of applications for differing handsets much easier; 33 manufacturers and carriers have signed up to the initiative and the first devices based on the new Google software are expected next year. Some consumers expressed disappointment, however, that the company did not unveil a “Google phone”, the subject of much recent hype.

TomTom, the leading maker of satellite-navigation devices, raised its offer for Tele Atlas by 41%, to euro2.9 billion ($4.2 billion), and said it would take a 28% stake in its Dutch compatriot. A merger between the two has been mooted since the summer, but Garmin, an American competitor, has also bid for Tele Atlas.

IAC/InterActiveCorp, an internet conglomerate, said it would spin off four divisions, including its Ticketmaster business. Barry Diller, IAC's boss, wants to refocus his firm around its fastest-growing businesses, such as Ask.com.

J. Sainsbury's share price plunged after an investment fund owned by the government of Qatar withdrew its offer to buy the British supermarket chain. The Qatari fund cited the cost associated with raising additional equity in the current market to cover liabilities for workers' pensions and was criticised for underestimating the scale of its commitment. It is the second time this year that Sainsbury's has found itself abandoned at the checkout by putative buyers.

Samsung Group became mired in scandal when its former top legal executive accused it of operating slush funds to bribe officials who may be thinking of investigating the affairs of the chaebol's chairman. The South Korean conglomerate vigorously denied the allegations.

Picket lines were manned outside studios in Hollywood and New York after the Writers Guild of America downed pencils and went on strike. At issue is how much the scribes should be paid for TV shows that are shown on the internet. Studios said that the dispute would cost jobs if filming was stalled.

Bling gets more expensive

The price of gold came within touching distance of its all-time high. The metal has been partly boosted by the weakness of the dollar. Institutional and retail investors have diversified into precious metals—silver is at a 26-year peak and platinum at a record high.