* Trump to speak on Tuesday on economic plans
* Investors fear lack of details from Trump
* Euro stronger as polls show Le Pen losing momentum (Adds market action, changes dateline from LONDON)
By Karen Brettell
NEW YORK, Feb 27 (Reuters) - The dollar was slightly weaker against a basket of currencies on Monday as investors worried that a speech by U.S. President Donald Trump on Tuesday would not provide many details on his economic agenda.
Treasury Secretary Steven Mnuchin said on Sunday that Trump would use the event to preview some elements of his sweeping plans to cut taxes for the middle class, simplify the tax system and make U.S. companies more globally competitive, with lower rates and changes to encourage U.S. manufacturing.
Mnuchin said last week that he wanted to pass “significant” tax legislation by August, which is later than many investors had hoped.
Mnuchin’s comments “seemed to indicate the details of tax reform will be known probably closer to the latter half of the summer, and we can most likely expect 3 percent growth towards the latter end of 2018,” said Bipan Rai, senior macro strategist at CIBC Capital Markets in Toronto.
“Both of those are somewhat at odds with what the market was hoping for in terms of near-term growth and more clarity around tax reform sooner rather than later,” Rai said.
The greenback was last down 0.19 percent against a basket of six major currencies at 100.90. It climbed as high as 103.82 on Jan. 3 as investors bet that Trump would enact policies that accelerate growth and boost inflation.
The dollar dropped 0.40 percent against the euro to $1.0603 and was little changed against the yen at 112.23 yen .
The euro also benefited from polls showing that far-right anti-EU leader Marine Le Pen was losing traction in France’s presidential race.
French independent candidate Emmanuel Macron would easily beat Le Pen in the second round of the election in May, two opinion polls showed on Sunday.
Sterling slipped to a 12-day low of $1.2382 on a report that Scotland was preparing to call another independence referendum when formal Brexit negotiations are triggered in March. (Editing by Lisa Von Ahn)