* Wall St little changed as Nike weighs
* U.S. bond yields firm in light, pre-Christmas trading
* Euro slides as pro-independence Catalan parties win seats
* Spanish bond yields hit over 1-month high
* Bitcoin plunges below $12,000, heads for worst week since 2013 (Updates with open of U.S. markets; changes byline, dateline; previous LONDON)
NEW YORK, Dec 22 (Reuters) - Global stocks were flat on Friday as a drop in shares of U.S. footwear company Nike helped offset any gains, while Spanish bond yields rose and European stocks stumbled after separatists prevailed in a Catalan election.
Nike shares dropped more than 4 percent after it forecast muted current-quarter revenue growth, highlighting its struggles to regain market share in North America from Adidas. Technology stocks were dragged down by Intel.
Despite the dip in mid-morning trading, Wall Street was poised to end the week higher after sharply rallying ahead of a $1.5 trillion tax cut bill that passed in Washington on Wednesday. U.S. President Donald Trump signed the tax overhaul into law on Friday.
Stock markets around the world shot higher as the law, seen boosting corporations and leading to economic growth, advanced through both chambers of the Republican-dominated Congress.
"We're in a bullish phase and investors have things to feel good about," said Andres Bakhos, managing director at Janlyn Capital LLC in Bernardsville, New Jersey.
Volumes are expected to be muted on Friday ahead of the Christmas holiday on Monday.
The Dow Jones Industrial Average fell 35.99 points, or 0.15 percent, to 24,746.3, the S&P 500 lost 4.15 points, or 0.15 percent, to 2,680.42 and the Nasdaq Composite dropped 15.39 points, or 0.22 percent, to 6,949.97.
MSCI's gauge of stocks across the globe shed 0.03 percent.
Spanish stocks and the euro fell while Spanish government bond yields hit one-month highs after Catalan separatists won a regional election, stoking concerns about the possible break-up of the euro zone's fourth-largest economy.
The pan-European FTSEurofirst 300 index lost 0.16 percent, while Spanish stocks were among the heaviest fallers, confirming analyst expectations that any shake-out from the Catalonia vote would be mostly confined to Spain. The IBEX fell 1.5 percent.
The euro fell against the U.S. dollar after the Catalan vote.
The euro slid 0.3 percent to $1.1835. Europe's common currency, though, was still up nearly 13 percent so far this year, on track for its best yearly performance in 14 years.
U.S. Treasury yields, which reached a nine-month peak after the American tax vote, pushed slightly higher as investors hung up their hats before Christmas.
The yield curve, while mildly flatter on the day, was on track for its largest weekly steepening since July following the bill's passage, which was seen as hastening the pace of interest rate increases.
In commodities, oil prices remained near their highest levels since 2015 on pledges from OPEC leader Saudi Arabia and non-OPEC Russia that any exit from crude output cuts would be gradual.
In cryptocurrencies, bitcoin once again became the most eye-catching mover, this time because of losses. Bitcoin plunged as much as 25 percent on the day at one point to below $12,000, having lost a third of its value since Sunday.
(Additional reporting by Ritvik Carvalho in London, Henning Gloystein and Dmitry Zhdannikov; Sruthi Shankar in Bengaluru, Gertrude Chavez-Dreyfuss and Richard Leong in New York; Editing by Nick Zieminski)