(Adds European market close; oil, gold settlement prices)
* MSCI index, Dow, S&P 500 set fresh intra-day highs
* European shares slip as Catalonia uncertainty unnerves investors
* Spain's main index posts worst day since Brexit vote
* U.S. Treasury yields flat to slightly higher ahead of payrolls
NEW YORK, Oct 4 (Reuters) - Global stocks were little changed on Wednesday after recent record highs driven by encouraging growth worldwide, while the dollar fell even as data revealed an accelerating U.S. service sector that could lead to higher interest rates in December.
U.S. Treasury debt yields rose on a stronger-than-expected reading for the Institute for Supply Management's index of non-manufacturing activity rose at its fastest clip in 12 years.
Oil prices were mixed on caution that rising U.S. crude output could scupper a crude rally that lasted for most of the third quarter.
MSCI's index of global stock performance set a fresh intra-day high, while on Wall Street the Dow and benchmark S&P
500 also notched new intra-day highs before paring some
The potential for tax reform has been driving the recent rally on Wall Street as geo-political tensions have ebbed and economic data remains strong, said Michael Arone, chief investment strategist at State Street Global Advisors in Boston.
"If the earnings season comes in as expected, you continue to see progress made on tax reform and you see diminished concerns about the geopolitical situation, the market wants to move higher," he said.
MSCI's index of equity performance in 47 countries gained 0.09 percent while the pan-European FTSEurofirst 300 index of leading regional shares closed down 0.13 percent 1,533.43.
The Dow Jones Industrial Average rose 26.03 points, or 0.11 percent, to 22,667.7. The S&P 500 gained 3.02 points, or 0.12 percent, to 2,537.6 and the Nasdaq Composite added 2.32 points, or 0.04 percent, to 6,534.03.
European shares fell as the impact of the crisis in Catalonia spread from Madrid and Spanish banks to the wider industry and euro zone region, particularly Italy.
Spain's IBEX posted its worst single-day loss in 15 months with a 2.85 percent decline.
Spanish government borrowing costs rose to their highest since March, stretching the gap over German benchmarks to the widest in over five months after Catalonia's secessionist leader said the region will declare independence in "days."
Catalonia will move next week to declare independence from Spain, a regional government source said, as a violence-marred vote on Sunday threatens the country's foundations and has unnerved financial markets.
Spain's 10-year bond yield rose as much as 7 basis points to 1.795 percent in early trades, according to Reuters data, the highest since mid-March.
Data from around the world showed a robust global economy.
U.S. private employers added 135,000 jobs in September, topping economists' expectations by 10,000, even as Hurricane Harvey and Irma "significantly impacted smaller retailers," a report by a payrolls processor showed.
The increase for the ADP National Employment Report was the smallest since October 2016. August private payroll gains were revised down to 228,000 from the original 237,000 increase.
In Europe, business across the euro zone grew rapidly in September as firms struggled to keep up with demand, a survey showed, with October looking likely to be lively as well.
IHS Markit's final composite Purchasing Managers' Index for the euro zone bounced to 56.7 last month from August's 55.7, in line with an earlier flash estimate and comfortably above the 50-mark that separates growth from contraction.
Japan's services sector expanded in September at the slowest rate in 11 months as the pace of new orders eased, but a raft of other data suggest the economic recovery remains intact even as momentum may have ebbed slightly in the third quarter.
Brent settled down 20 cents at $55.80 per barrel, while U.S. crude fell 44 cents to settle at $49.98 a barrel.
The dollar index fell 0.1 percent, with the euro up 0.17 percent to $1.1762. The Japanese yen strengthened 0.08 percent versus the greenback at 112.75 per dollar.
Benchmark 10-year notes was flat in price to yield 2.3301 percent.
(Reporting by Herbert Lash; Editing by Nick Zieminski)