The dollar gained this afternoon after core inflation in the US had the biggest back-to-back gain in three years.

The euro fell versus the dollar and yen before European bank stress-test results and an Italian vote on an austerity package.

But the Dollar Index was little changed after Standard and Poor's said there's a 50 per cent chance the US will lose its top credit rating even if Congress reaches agreement on raising the debt ceiling to stave off a default.

"Having a slightly high reading of core inflation is something that grabbed the attention of the market today, which is our reason why the dollar should be benefiting after Bernanke's speech that raised the idea that we could have more easing or the beginning of an exit," said David Mann, regional head of research for the Americas at Standard Chartered in New York.

The dollar rose 0.2 per cent to $1.4121 versus the euro at 9.04am in New York, from $1.4143
yesterday. It was 0.1 per cent higher versus the Japanese currency at 79.18, from 79.14. The yen was little changed against the euro to 111.90, from 111.92.

The so-called core measure of the cost of living in the US, which excludes more volatile food and energy costs, increased 0.3 per cent for a second month. Economists projected the core gauge would rise 0.2 per cent.

Bloomberg