NOT only are the students at the Indian Institute of Management Ahmedabad (IIMA), the country’s top business school, sickeningly clever. They also work disgustingly hard. “Four hours,” grins a first-year student on the two-year MBA course, when asked how much sleep he gets a night. He is debating whether to try to join McKinsey, a consultancy, pursue an economics doctorate at an American Ivy League university or stay in India and try to make a difference, perhaps by joining the elite corps of the civil service.

IIMA takes in about 450 people a year on its main course and has long supplied a disproportionate chunk of high-flyers in Indian finance and business. It now is leaping up the global rankings of business schools, too, from 85th place in 2010 to 56th in The Economist’s latest league table.

That is despite a modest budget. Income was $30m last year, or 6% of Harvard Business School’s purse. The campus is smart, but has a distinct lack of suicidally expensive Astroturf facilities. For a decade IIMA has done without state funding. Half its income comes from student fees—a two-year course costs about $28,000, including digs, with 95% of students raising cheap loans to pay for it. The rest mainly comes from short courses for corporate warriors in need of pepping up.

The rankings may understate IIMA’s strength. They give weight to research, and IIMA has so far only cared about teaching. But that is changing, says S.K. Barua, its boss. Although it will not go down the path of some Chinese universities—hiring foreign academic rock stars to give the research rankings a boost—IIMA’s faculty are being prodded to publish more papers. “In another five to seven years we ought to be in the top 20 schools,” says Mr Barua.

IIMA rates poorly on diversity, having few foreigners and women. But in other ways, it has changed, partly due to government quotas. The typical student used to be from a city, to have studied at a posh English-language school and to boast an undergraduate degree from an elite engineering college. Today engineers still dominate the intake. But they are as likely to come from a small town and have studied at a provincial college and a non-English-speaking school.

IIMA’s intake has begun to reflect India, then. But its output is mildly concerning for India’s economic future. About half of leavers enter finance or consulting: one hotshot talks fondly of his internship on a London dealing desk with Deutsche Bank. A third go abroad. Very few start their own firms in India. Mr Barua says that more take the plunge after a few years of work and once they have repaid their debts. Include them and just over a tenth of IIMA students are involved in start-ups.

It would be good for India if that share rose. For now, though, its main source of entrepreneurs is likely to remain its traditional business classes, not least the people of Gujarat, the state in which IIMA is based, who are famous for their acumen. Asked how many Gujaratis attend the school, one dog-tired student replies, “They don’t need to. It’s in their blood.”