* Dlr index drops as low as 78.111, its lowest this year
* Aussie climbes to 10-mth high and sterling hits 9-mth peak
* Euro reverses gains to 2-mth high
By Satomi Noguchi
TOKYO, Aug 3 (Reuters) - The dollar fell broadly on Monday and hit its lowest point this year against a basket of currencies after higher oil prices, steady global stock markets and U.S. GDP data boosted investments in riskier assets.
The Australian dollar, a commodity-linked currency, climbed to a 10-month high versus the dollar, helped partly by oil prices holding firm around $70 a barrel in Asian trade after jumping nearly 4 percent late last week.
Commodity prices rose on Friday as data showing U.S. gross domestic product for the second quarter fell at a 1.0 percent annual rate, below analysts expectations for a 1.5 percent drop, raising hopes that fuel demand would recover.
The dollar's slide was driven largely by technical factors such as stop-loss buying in sterling, which hit its highest level in nine-months, traders said.
"The dollar looks set to fall further with the dollar index breaking decisively below recent lows," said a trader for a Japanese trust bank.
The trader also said the sustainability of the dollar's broad drop will be tested by a slew of U.S. economic data out this week starting with the Institute for Supply Management's manufacturing index for July, which is due later in the day.
The biggest market focus will be Friday's U.S. job reports as U.S. economy appears to be picking up steam even without its strongest engine -- consumer spending.
Masafumi Yamamoto, head of FX strategy for Japan at Royal Bank of Scotland, said the Aussie would rise further against the dollar and the yen this week if U.S. data adds to hopes for an economic recovery.
But Yamamoto also said in his note to clients that further gains in the euro were hard to see with caution ahead of more earning reports from European banks this week.
The euro quickly reversed earlier gains to a two-month peak against the dollar in choppy trade as Japanese exporters sold the euro to repatriate overseas earnings, traders said.
HSBC, Europe's biggest bank, and Barclays are scheduled to report half-year results later in the day followed by Standard Chartered on Tuesday and Lloyds Banking Group on Wednesday.
Results from major European banks are expected to be buoyant after a strong recovery in capital markets activity this year, but losses on mortgages and commercial loans will weigh on the retail parts of the businesses, analysts predict.
The dollar index, a gauge of the U.S. currency's performance against six other major currencies, fell as low as 78.111, the lowest since mid-December, before recovering to trade at 78.337, near flat from late New York trade on Friday.
The Australian dollar climbed as high as $0.8394 on the Reuters dealing system, the highest since late September.
Traders said the Aussie is being supported by expectations that the Reserve Bank of Australia may drop a key reference on monetary easing at its policy meeting on Tuesday while keeping the cash rate unchanged at 3 percent.
The euro fell 0.1 percent to $1.4248 after rising as high as $1.4310 on trading platform EBS, its highest since early June.
Sterling jumped as high as $1.6780, its highest in nine months, before stabilising at $1.6737, up 0.2 percent on the day.
Against the yen, the euro was flat at 135.02 yen after falling as low as 134.78 on EBS from the day's high of 135.44 yen. The dollar was also unchanged at 94.75 yen. (Additional reporting by Masayuki Kitano; Editing by Joseph Radford)