By Edward Krudy

NEW YORK (Reuters) - Global markets traded cautiously on Wednesday, a day before the United Kingdom votes on whether to stay in the EU, with Wall Street stocks easing lower and sterling inching up.

Oil fell back below $50 per barrel and the yen was down against the dollar, with the latest polls showing a slight tilt toward leaving the European Union when Britons go to the polls on Thursday.

The "Leave" campaign holds a 1-2 point lead over the "In" camp ahead of Thursday's membership referendum, according to surveys published by polling firms Opinium and TNS, reversing a tilt earlier this week toward "Remain."

Markets have been resilient so far this week, with investors unwilling to make big bets in either direction over the last two days. Opinion polls have led to volatility in asset prices, although Monday's large rally in "risk assets" has held as markets appear to lean toward the view that the United Kingdom will remain in the EU.

"I think the result of the Brexit vote is 50/50, and it will probably be very tight," said Olivier de Berranger, fund manager at French firm La Financiere de L'Echiquier, which manages around $9 billion in assets.

Sterling rose around 0.4 percent to $104.38, edging away from Tuesday's 5-1/2 month high of $1.4781. The pound, which briefly turned negative after the latest polls were released, has risen 5 percent since dropping to a three-month low of $1.4010 last Thursday.

Britain's main share index hit a two-week high on the eve of Thursday's vote before surrendering half the day's gains in the last minutes of trading.

U.S. stocks gave up morning gains and closed lower.

The Dow Jones industrial average fell 48.9 points, or 0.27 percent, to 17,780.83, the S&P 500 lost 3.45 points, or 0.17 percent, to 2,085.45 and the Nasdaq Composite dropped 10.44 points, or 0.22 percent, to 4,833.32.

The MSCI's all-country world stock index edged up 0.1 percent but has still gained 2.1 percent so far this week.

Putting a floor under markets, betting patterns with bookmakers have shown a re-opening of the gap in favor of "Remain" after the murder last week of a pro-EU lawmaker appeared to derail the "Leave" campaign.

Europe's stock markets also pared gains into the close. Europe's FTSEuroFirst index of 300 leading shares was up 0.5 percent, Germany's DAX was up 0.6 percent, France's CAC 40 up 0.3 percent and Britain's FTSE 100 up 0.6 percent.

The yen slipped 0.3 percent against the dollar to 104.41 yen, and the euro rose 0.5 percent to $1.1296.

For the latest Reuters news on the referendum including full multimedia coverage, click.

Fed chief Janet Yellen said on Tuesday the risk of Brexit needed watching "very carefully," and added that the central bank's ability to raise interest rates this year may hinge on a rebound in hiring.

Yellen concluded her testimony in front of the U.S. House Financial Services Committee on Wednesday, with little further indication about the central bank's thinking on the U.S. economy and the timing of interest rate hikes.

Benchmark 10-year U.S. bond prices edged higher, yielding 1.69 percent. Germany's 10-year yield edged up a basis point to 0.06 percent.

Gold cut some earlier losses after the polls but edged lower into the afternoon. Spot gold fell 0.2 percent to a near-two-week low of $1,265.38 an ounce.

Brent crude futures fell 74 cents to $49.88 per barrel. The new benchmark August contract for U.S. crude futures fell 1.5 percent to $49.09.

(Additional reporting by William Schomberg, editing by Larry King and Nick Zieminski)