When Goldman Sachs speaks, Wall Street listens – this axiom has held true for quite a few years. However, the investment bank's expertise is not limited to financial institutions alone, but encapsulates national and global economies as well. Hence, when the latest report from the exalted institution says that incomes in India will likely be close to the global average by 2030, it surely is time to smile.

That, and other amazing findings like the addition of two billion members to the middle-class club by 2030, is among the nuggets unveiled in a research report by Jim O'Neill, global chief economist at Goldman Sachs. According to him, global income distribution is getting narrower, not wider. So while there is a lot of focus on widening inequality and the embattled middle class in developed countries, globally the opposite is true.

The report looks at the Expanding Middle – the exploding world middle class and falling global inequality. By 2030, incomes in China and India are projected to be close to the global average. The middle-class is defined as composed of as those with incomes between $6,000 and $30,000 in purchasing power parity (PPP) terms.

A simple way to see this is to look at the list of the seven largest economies (the 'true G7') in 1960, 2007 and 2050. In 1960, the largest economies were all essentially ''developed'' countries from the higher income groups. By 2007, that has already clearly begun to change, with China in the top seven and Brazil, India and Russia not far behind. But developed countries still dominate the rankings.

From here on, the shift is likely to accelerate. These shifts could be a significant influence on spending patterns, resource use, and environmental and political pressures. In 2050, India would have the 3rd rank on the top seven nations list with an income ranking of 61.

The report goes on to say that the phenomenon can be seen in two related ways. The first is the ''shift in spending power towards middle-income economies'' (and away from the richest countries), to a point where they may dominate global spending for the first time in decades, as the largest population countries enter the middle-income group.

The second is the ''shift in spending power towards middle-income people'' and the explosion of a global 'middle class' on a scale never seen before. Over the last 10 years, the world has already seen unprecedented expansion in this group. But the pace of expansion here is likely to pick up much further still, reaching its peak in about a decade.

The distribution of global incomes could narrow significantly further, even if inequality within some countries remains high or rises further, as middle income countries continue to move through the pack. World could outstrip anything which exists globally for decades, and will peak (at around 20 million per year) around the same time as India.

Already by 2020, one third of the new entrants to the world middle class will come from outside China and India. And this percentage could reach half by 2030.

A result of these shifts would be a world that could continue to be dominated by the rise of the BRIC (Brazil, Russia, India and China), the N-11 (The Next Eleven (or N-11) are eleven countries - Bangladesh, Egypt, Indonesia, Iran, Mexico, Nigeria, Pakistan, Philippines, South Korea, Turkey, and Vietnam - identified by Goldman Sachs as having a high potential of becoming the world's largest economies) and a handful of other emerging countries.

From a global perspective, more people are set to share more of the world's income than has been true for decades. ''So whether one sees the rise of the large emerging economies, and the last decade of global growth and globalization, as a force that is driving greater inequality, depends more on vantage point than current debate often reflects,'' says O'Neill.