The dollar index hit a three-month low on Monday, hurt by worries that the U.S. economy's recovery is losing steam, while the high-yielding Australian dollar reached a three-month high, buoyed by a rise in equities.

The dollar has been hobbled by concerns over the U.S. economy after recent economic data undershot market expectations, while European data and many company results have been stronger -- keeping investors buying riskier assets.

Robust results from HSBC (HSBA.L)(0005.HK) and BNP Paribas (BNPP.PA) helped risk sentiment on Monday, as European shares rose close to 2 percent .FTEU3.

It may not be a bad trade in the thinned liquidity of summer months to trade up the European currencies which have been rising on the strength of their economic data, said Hans Redeker, head of FX strategy at BNP Paribas.

But analysts said the perceived better risk sentiment outside of the United States was unlikely to be maintained if the world's biggest economy continued to underperform.

The dollar index, which measures the greenback's value against a basket of currencies, hit a three-month low of 81.354 .DXY, dipping below support near 81.44, which is roughly a 50 percent retracement of its November to June rally.

By 1055 GMT (6:55 a.m. EDT), it was at 81.389, down 0.2 percent on the day.

We're seeing a disconnection as U.S. data stays weak yet risk appetite is strong. Weak U.S. data will translate into risk aversion at some point, said Tom Levinson, currency strategist at ING.

Latest data from the Commodity Futures Trading Commission showed the biggest accumulation of net dollar short positions from speculators since December 2009.

The euro was up 0.2 percent from late U.S. trading on Friday to $1.3072, near a three-month high of $1.3107 marked last week.

Key resistance was at $1.3125, the 38.2 percent retracement of the fall from late November to early June, while options traders noted barriers in place at $1.3200, $1.3250 and $1.3300, said to expire from the end of August into early September.

Sterling hit a six-month high versus the dollar of $1.5820 and outpaced the euro, rising to a four-week high of 82.64 pence.

AUSSIE RISES, YEN SLIPS

The dollar also fell against the high-yielding Australian and New Zealand dollars, with the Aussie hitting a three-month peak at $0.9136. They were buoyed by gains for global equities, which rose 0.9 percent .MIWD00000PUS.

China's official purchasing managers' index fell to 51.2 in July from 52.1 in June, but still remained above the growth-versus-contraction level of 50.

The yen slipped broadly and pulled back a bit from an eight-month high versus the dollar of 85.95 yen hit late last week. It was last at up 0.3 percent to 86.75 yen.

Japanese finance minister Yoshihiko Noda said on Monday excessive yen movements were undesirable because of the currency's impact on the economy and markets, and he was watching currency moves closely.

The dollar was battered after data on Friday showed the U.S. economy slowed to a 2.4 percent annual rate in the second quarter.

Traders will look to the Institute for Supply Management's manufacturing index due out at 1400 GMT, which is seen falling to 54.1 in July from 56.2 the previous month.

The dollar's performance will hinge on the performance of U.S. non-farm payrolls data due on Friday, which will set the stage for the Fed's policy-setting meeting on August 10, BNP's Redeker said.

(Additional reporting by Tamawa Desai; Editing by Susan Fenton)

China Japan BNP Paribas