* U.S. government shutdown possibility looms over tax debate
* Bitcoin rockets to another record high
* Aussie slips on downbeat signals in Q3 GDP data
* Graphic: World FX rates in 2017 http://tmsnrt.rs/2egbfVh
By Jemima Kelly
LONDON, Dec 6 (Reuters) - The dollar edged broadly lower in a quiet market on Wednesday as concerns about a possible U.S. government shutdown offset optimism about progress on tax reform legislation.
Analysts said it was unlikely for there to be any big moves in the dollar until at least after Friday's closely watched non-farm payrolls report, and perhaps not until next week's U.S. Federal Reserve policy meeting is out of the way.
Bitcoin's moves dwarfed any traditional currency's once again, with the cryptocurrency hitting a new record high of more than $12,500 BTC=BTSP , up almost 7 percent on the day. It is on track for its strongest quarter since 2013 after almost tripling in price since the start of October. dollar index, which tracks the greenback against a basket of six major currencies, inched 0.1 percent lower to 93.297 .DXY= .
It hit a five-day low of 111.99 yen JPY=EBS , down half a percent on the day.
The United States' Republican-controlled House of Representatives voted on Monday to go to conference with the Senate to begin formal negotiations on a tax reform bill, with the Senate expected to hold a similar conference vote later this week - a development seen as positive by markets.
But in the meantime, the possibility of a U.S. government shutdown looms, if lawmakers fail to reach a budget accord this week. Government funding is set to expire on Friday. we know, in general they (U.S. Congress) find a solution, even if it's a last-day solution," said Commerzbank (DE:CBKG) currency strategist Esther Reichelt.
"But ... in general political turmoil is an underlying weight on the dollar and it's one of the reasons the euro is above the $1.18 level at the moment."
The euro was steady on the day at $1.1820 EUR= .
Expectations of higher U.S. rates underpinned the dollar, though a flattening U.S. Treasury yield curve kept investors' hopes in check.
Fed funds futures prices show investors expect the U.S. central bank to hike rates at next week's meeting, with futures prices showing a zero percent chance of rates remaining at their current level of 1.00-1.25 percent.
The Australian dollar slipped 0.4 percent to $0.7580 AUD=D4 , within sight of its five-month low of $0.7532 plumbed on Nov. 21, after weak growth data. Canadian dollar edged down 0.1 percent to C$1.2699 against its U.S. counterpart ahead of a Bank of Canada policy meeting later in the day.
"The BoC should leave rates unchanged and the main question is whether it offers any hints with respect to the January meeting," wrote Credit Agricole (PA:CAGR) analysts in a note to clients.
"If the BoC is seriously considering (another) hike, it could offer a hint by referring to some evidence of building underlying price pressures. Market-implied odds are at 40 percent for January at the moment, so it would take at least some upgrade to the statement to push them above 50 percent."