* World share markets slip, U.S. bond yields flat after early decline
* Wall Street lower as retail earnings disappoint
* Investors warily eye Thailand martial law declaration (Updates with U.S. markets open; changes dateline; previous LONDON)
By Caroline Valetkevitch
NEW YORK, May 20 (Reuters) - Global stock indices were lower on Tuesday after weaker-than-expected earnings, while the dollar fell for a fifth straight session against the yen.
U.S. stocks were pulled down by retailers, including TJX Companies, which posted lower-than-expected quarterly revenue.
A persistent fall in U.S. Treasury yields, reflecting uncertainty about global economic growth, has undermined the dollar recently. But U.S. Treasuries were mostly flat on Tuesday.
"There's a little bit of risk-off sentiment given the declines in stocks," said Kim Rupert, managing director for fixed income at Action Economics in San Francisco.
Concerns surrounding Ukraine remained an "undercurrent," she said.
MSCI's all-world equity index, which tracks shares in 45 nations, was down 0.2 percent, while European shares slipped 0.1 percent.
Vodafone shares fell after the company wrote down the value of some of its European businesses, citing fierce competition and regulatory changes in Europe.
On Wall Street, the Dow Jones industrial average fell 46.39 points, or 0.28 percent, at 16,465.47. The Standard & Poor's 500 Index was down 4.17 points, or 0.22 percent, at 1,880.91. The Nasdaq Composite Index was down 10.29 points, or 0.25 percent, at 4,115.52.
Investors will soon turn their focus to minutes from the last Federal Reserve policy meeting, due on Wednesday, and whether that will give any hints on the likelihood and timing of rates rises.
At the same time, markets are optimistic over fresh support from the European Central Bank, one of the few central banks still keeping monetary policy loose.
In mid-morning trading, the dollar fell 0.3 percent to 101.26. The pair traded below the 200-day moving average, a key technical gauge, for a second straight day.
The Australian dollar was the biggest mover of the day, falling to a two-week low against the greenback on a slide in prices for iron ore, the country's biggest export earner.
Benchmark 10-year U.S. Treasury note prices were last up 3/32 to yield 2.525 percent, from a yield of 2.536 percent late Monday.
Nervousness also washed in from Asia, where Thailand declared martial law overnight after months of unrest .
Thailand's baht initially fell against the dollar, then steadied as dealers suspected the Thai central bank had intervened. Bangkok's SET index pared some of its early losses to end down 0.8 percent.
MSCI's broadest index of Asia-Pacific shares outside Japan slipped 0.4 percent.
Additional reporting by Marc Jones and John Geddie in London; Editing by Dan Grebler