GLOBAL MARKETS-Yen posts biggest weekly gain since 2008, stocks fall

* Soaring yen dominates world markets

* U.S (Other OTC: UBGXF - news) ., Europe stocks fall on disappointing earnings

* Oil has $50/barrel in its sights

By Herbert Lash

NEW YORK, April 29 (Reuters) - The yen hit an 18-month high on Friday as investors bet the Bank of Japan might be done adding fresh stimulus to the economy, while stocks in Europe and Wall Street headed lower as earnings failed to inspire higher valuations.

U.S. equities fell about 0.7 percent, following declines in Europe where major stock indexes fell 2 percent or more.

The yen was on track for its biggest weekly gain since the 2008 financial crisis, also spurred by a weak reading of U.S. economic growth on Thursday and the Federal Reserve's cautious tone this week.

The yen has gained 3 percent since Thursday's meeting where the BOJ held monetary policy steady in the face of soft global demand and the yen's recent sharp rise. The BOJ move defied expectations for increased stimulus measures to fight deflation.

The dollar was last down 0.9 percent against the yen at 107.11 yen after hitting an 18-month low of 106.92. The dollar was off about 4 percent against the yen for the week, on track to post its biggest weekly loss since October 2008.

The dollar also tumbled against the euro, with the euro hitting its highest level against the dollar in two and a half weeks, at $1.1447. The euro was last up 0.81 percent against the dollar at $1.1443.

"It (Other OTC: ITGL - news) 's just a continuation of momentum after the BOJ policy announcement," said Vassili Serebriakov, currency strategist at BNP Paribas (LSE: 0HB5.L - news) in New York.

European equities were headed for their biggest weekly decline in one month, with the FTSEurofirst 300 index of leading European shares down 2 percent and the euro zone blue chip Euro STOXX 50 down 3 percent.

MSCI (NYSE: MSCI - news) 's all-country world stock index fell 0.56 percent.

On Wall Street, the Dow Jones industrial average fell 115.5 points, or 0.65 percent, to 17,715.26. The S&P 500 slid 14.36 points, or 0.69 percent, to 2,061.45 and the Nasdaq Composite lost 36.86 points, or 0.77 percent, to 4,768.43.

Rahul Shah, chief executive of Ideal Asset Management in New (KOSDAQ: 160550.KQ - news) York, said valuations are high, so earnings must exceed a high bar for the market to go higher.

"We've seen that from Amazon and Facebook (NasdaqGS: FB - news) , and those shares have been awarded accordingly," Shah said. "But the rest of the earnings reports have been less inspiring to say the least, so it's hard to see the overall market march much higher."

Brent crude trimmed gains after its biggest monthly rise in seven years. It touched 2016 highs as a weak dollar and falling U.S. production tempered concerns about an oil glut.

A looming rise in Middle East output capped gains, but investor sentiment held the optimism that has helped lift oil futures nearly 80 percent from January lows.

Brent futures traded at $47.76 a barrel, down 0.8 percent and U.S. crude was off 0.7 percent at $45.71.

U.S. Treasury prices fell, with the benchmark 10-year note down 2/32 in price to yield 1.8457 percent.

(Reporting by Herbert Lash; Editing by James Dalgleish)