The US economy grew at a higher clip of 2.1% in the third quarter ended 30 September, 2015, though much lower than the 3.9% growth recorded in the previous quarter, prompting an economist to call it a "tortoise recovery".

The second estimate of 2.1% is higher than the first estimate of 1.5% reported by the US Commerce Department made in October; the third and final estimate will be out on 22 December.

The increase in GDP growth was mainly due to an upward revision of inventories from the first estimate. However, this was partially offset by a downward revision in consumer spending, according to the data released by the Bureau of Economic Analysis on 24 November.

"The inventory revision was even bigger than we expected," said Diane Swonk, chief economist at Mesirow Financial in Chicago.

The buoyancy in growth in the third quarter is likely to increase speculation that the US Federal Reserve "is ready to raise interest rates" in December.

"Domestic demand in the US economy remains very solid, something that will surely give comfort to the Fed as it ponders its next move," said Robert Kavcic, a senior economist at BMO Capital Markets, reports the BBC.

The lacklustre pace of growth is "tortoise recovery", wrote Goldman Sachs chief economist Jan Hatzius in his note to clients.

"While this expansion may go uncelebrated, growth in fact has been good enough to achieve a great deal of cumulative progress in the labor market," said Hatzius.

The data showed profits of American financial companies decreased $8.5 billion in the third quarter, compared to an increase of $34.6 billion in the quarter ended 30 June, 2015.

Taxes on corporate income were up by $2.3 billion, as against an increase of $31.3 billion in the June quarter.