Engaging India is a weekly online column analysing the issues, trends and forces behind the business and politics shaping India and its impact on the world. Engaging India appears every Thursday morning exclusively on FT.com India, a dedicated online section on India, and is written by Jo Johnson, the Financial Times’ South Asia bureau chief; Amy Yee, New Delhi correspondent; and Joe Leahy, Mumbai correspondent.

If overseas Indians seem ubiquitous as entrepreneurs, it’s not your imagination. A report released earlier this month showed that of US technology companies founded by immigrants over the past decade, 26 per cent had an Indian founder - more than those from the UK, China, Taiwan and Japan combined.

“What is clear is that immigrants have become a significant driving force in the creation of new businesses and intellectual property in the US - and that their contributions have increased over the past decade,” according to the report by researchers at Duke University in North Carolina and the University of California at Berkeley.

Immigrant-founded engineering and technology companies surveyed in the report generated $52bn in sales and employed 450,000 workers in 2005.

The report also showed that immigrants have made significant contributions to innovation. Foreign nationals residing in the US were inventors or co-inventors in 24.2 per cent of international patent applications filed from the US last year, based on an analysis of the World Intellectual Property Organization (WIPO) patent databases. That does not even include immigrants who became citizens before filing a patent.

Patents filed by non-citizen immigrants have steadily increased in recent years, from 7.3 per cent in 1998 to 24.2 per cent last year. The largest group of immigrant non-citizen inventors were Chinese born in mainland China and Taiwan, followed by Indians, Canadians and British.

Non-immigrant citizens who filed patents are typically foreign graduate students completing their PhDs, green card holders awaiting citizenship, and employees of multinationals on temporary visas.

In Silicon Valley, California’s technology hub, the influence of immigrants is only magnified. More than half (52.4%) of Silicon Valley start-ups had one or more immigrants as a key founder. From 1995 to 2005, Indians were key founders of 15.5 per cent of all Silicon Valley start-up, and immigrants from China and Taiwan were key founders in 12.8 per cent.

The report comes as the US continues to grapple with tighter visa and immigration policies that threaten to drive immigrants, including foreign graduate students and highly-skilled workers, elsewhere.

“There is a serious problem brewing on this front,” said Vivek Wadhwa, an author of the report and executive-in-residence at Duke University. “Unless we fix the number of green cards [which allow US permanent residence] for skilled immigrants for the top skilled immigrant groups, these temporary workers and students/PhD’s will have to go back…this is bad for the US.”

But as India’s booming economy yields more opportunities and better living conditions for the affluent, overseas Indians are themselves considering a return to the “motherland”.

“The situation is completely reversed,” said Deepak Gupta, managing director at the executive search firm Korn/Ferry. “NRIs (non-resident Indians) from all around the world want a piece of the action in India.”

Mr Gupta, based in New Delhi, said just a few years ago Korn/Ferry would receive one or two inquiries a quarter from overseas Indians interested in working in India. Now resumes from overseas Indians looking for opportunities in India are “flying in from all over the world” and Korn/Ferry receives several inquiries each week.

“It’s almost to a point where it’s hard to manage those interest levels,” added Mr Gupta.

Keen interest from overseas Indians was palpable at a conference in New Delhi this month devoted to the Indian diaspora. More than 1,200 people attended the annual “Pravasi Bharatiya Divas” jamboree where Prime Minister Manmohan Singh and top government officials stressed the importance of the Indian diaspora.

Between 20m to 25m overseas Indians are spread out around the world in locales as diverse as Singapore, London, New Jersey, Kenya and Trinidad. India’s government is working on policy initiatives to make it easier for overseas Indians to engage with India, whether through more attractive tax policies or creation of a government office devoted to facilitating investments.

Participants at the conference agreed there has been a shift in sentiment as India’s government and its diaspora begin to take each other seriously.

“There is a huge difference in attitude over the last five years,” said Jag Johal, an investment fund manager of Indian descent who lives in South Africa and carries a UK passport. “Before, we were treated with some hostility. Now the government is actively encouraging participation from overseas Indians.”

India is growing increasingly aware that it has much to be gained from tapping the strengths of overseas Indians. It is a formidable resource.

The disproportionately large number of Indian entrepreneurs in the US, for example, is no coincidence, said Mr Gupta of Korn/Ferry. He alluded to the fierce competition in India to be admitted to universities and a sense of struggled instilled in Indians as children.

“It’s a competitive process all the way to the first job you get,” he said. When highly-skilled Indians “go to a fair and open market like the US, they stand out.”

Mr Wadhwa of Duke pointed out that Indian immigrants in the US often have very strong science and maths training, tend to be more entrepreneurial than those that stay at comfortable jobs in India and already speak English. In India they may be held back by bureaucracy, corruption and bad infrastructure.

“But take entrepreneurs who are able to succeed with all the restraints that India and its society imposes on them and transplant them to a fertile land and they flourish.”

One participant in this month’s diaspora conference theorised that the prevalence of Indian entrepreneurs overseas is sparked by necessity. Immigrant Indians may face more challenges breaking into entrenched corporate cultures and so strike out on their own, he suggested.

Yet even apart from founding their own companies, overseas Indians have climbed to the top ranks of industry, academia and the arts.

Manmohan Singh told the diaspora conference: “I want every Indian living and working in India to aspire for the global recognition that a Zubin Mehta [classical music conductor], a Lakshmi Mittal [chief executive of Arcelor Mittal], an Indra Nooyi [chief executive of Pepsi], an Amartya Sen [Nobel prize winner for economics] or a Kalpana Chawla [astronaut] gets when they go overseas.”

Certainly India hopes to transplant the successes of overseas Indians back to home soil. And these days, it is not hard to convince growing numbers of them of the opportunities growing at their roots.