* Euro share of global FX reserves biggest since late 2014
* Yen share of reserves rebounds to largest in 15 years (Adds details, background)
March 30 (Reuters) - The U.S. dollar's share of currency reserves reported to the International Monetary Fund declined in the final quarter of 2017 to a four-year low, as other currencies' shares of reserves grew, data released on Friday showed.
The share of dollar reserves has declined for four straight quarters as the greenback weakened in 2017 due to faster growth outside the United States and bets that other major central banks would consider reducing stimulus. Still the dollar has remained the biggest reserve currency by far.
Global reserves are assets of central banks held in different currencies, mainly used to support their liabilities. Central banks sometimes have used reserves to help support their respective currencies.
"Reserve managers in Q4 liked (yen) and 'other currencies,"' Steven Englander, head of research and strategy with Rafiki Capital Management, wrote in a research note. "The limited (U.S. dollar) buying is not surprising. Reserve managers buy (U.S. dollar) when they have to -- they rarely want to buy."
Reserves held in U.S. dollars rose to $6.28 trillion, or 62.7 percent of allocated reserves, in the fourth quarter, from $6.13 trillion, or 63.5 percent, in the third quarter. The share of U.S. dollar reserves declined to its smallest level since reaching 61.24 percent in the fourth quarter of 2013, IMF data showed.
Ranked second behind the greenback, the euro's share of global reserves reached 20.15 in the fourth quarter, up from 20.05 percent in the third quarter. This was its biggest share in three years, but well below the single currency's peak share of reserves at 28 percent in 2009.
The yen's share of currency reserves rebounded from a dip in the third quarter to 4.89 percent, which was its biggest since the fourth quarter of 2002, IMF data showed.
China's share of allocated currency reserves was 1.23 percent, up from 1.12 percent from the prior quarter. The IMF had reported the yuan's share of central bank holdings for the first time in the fourth quarter of 2016.
IMF data also showed that global reserves climbed to $11.425 trillion, which was the highest since the second quarter of 2015 and was up from $11.297 trillion in the third quarter.
The total amount of allocated currency holdings also grew to $10.019 trillion from $9.646 trillion in the third quarter.
Allocated reserves now include part of China's official reserves, with full currency allocation disclosure set to take two to three years. With China's disclosure, the share of allocated reserves as a percentage of the total increased to 87.69 from 85.39 percent.
Global unallocated reserves, or those that have not been reported to the IMF, fell to $1.406 trillion from $1.650 trillion in the previous quarter.
Unallocated reserves represented only 12.31 percent of total global FX reserves, down from 14.6 percent in the third quarter. It is widely believed in the currency market that part of China's reserves were in the unallocated pool.
The British pound, Swiss franc, Australian and Canadian dollars also saw their shares in global reserves expanded slightly from the third quarter, according to IMF data. (Reporting by Richard Leong; Editing by Sandra Maler)