* Euro hits 15-month high of $1.4521 on EBS
* Dollar/yen, euro/yen regain some ground after sell-off
* Yen pressured as short-covering and profit-taking fade
(Rewrites, adds quotes, U.S. data, updates prices, changes byline, dateline; previous LONDON)
By Gertrude Chavez-Dreyfuss
NEW YORK, April 13 (Reuters) - The yen fell on Wednesday after rising four straight days against the dollar and euro, as risk appetite improved following gains in global stocks from better-than-expected JPMorgan earnings.
The Japanese currency's downtrend should stay intact as long as risk appetite holds up. The negative impact on the economy of the recent massive earthquake is expected to ensure Japanese monetary policy remains ultra-loose for a prolonged period.
There had been a retracement in risky trades the past few days because of Japan's nuclear power crisis and some lingering worries about euro zone debt problems, resulting in yen strength. Analysts warned that cautious market sentiment could return by Thursday.
The yen tends to fall when there is increased risk-taking in the market as investors sell assets funded by the low-yielding Japanese currency in carry trades.
"There is a more of a positive risk environment today," said Vassili Serebriakov, currency strategist at Wells Fargo in New York. "But this may change tomorrow, and the yen may be back up tomorrow. It just goes to show how risk sentiment plays a big part in the currency market."
U.S. stocks opened higher after JPMorgan Chase's earnings beat expectations and spurred bets that other banks' results will be strong.
The euro, meanwhile, edged higher against the greenback, hitting a fresh 15-month high, boosted by reported demand from sovereign names looking to recycle dollar proceeds.
The single euro zone currency would be vulnerable to pullbacks after racking up gains, but overall, the euro remained supported by the prospect of more interest rate increases by the European Central Bank.
In early New York trading, the dollar was up 0.5 percent at 84.03 yen after sliding more than 1.2 percent on Tuesday for its biggest one-day percentage drop in four months.
The euro was up 0.5 percent on the day at 121.67 yen, although it was well below an 11-month high of 123.33 yen hit on Monday.
The euro was little changed at $1.4484, having earlier hit $1.4521, a 15-month peak on EBS trading platform, narrowly surpassing Tuesday's $1.4520 high.
Further supporting the euro's positive outlook were comments from ECB Governing Council member Luc Coene. On Wednesday, Coene said the ECB's interest rate increase last week should not be considered as an isolated decision. For more click on.
The euro's gains were slowed by persistent option-related offers. Traders said a barrier at $1.4530 was being defended, expiring on Friday. A break above there would target the 2010 highs around $1.4582.
Technical analysts said the uptrend remained intact while the currency is above $1.4250/80 -- the area from which the euro bounced toward current highs. A sustained break above $1.4600 could open up the path for a test of $1.5000.
The options market, however, isn't following the move in spot prices.
Options investors are still betting on a decline in the euro against the dollar, with risk reversals for one-month options still showing a solid bias for "puts". On Wednesday, euro risk reversals were at -1.35.
Analysts said there is a tug-of-war going on in the options market between the market makers, which provide liquidity, and the institutional buyers, which seem skeptical that the euro will keep on rising given persistent euro zone fiscal stress.
Commodity-linked currencies such as the Australian and New Zealand dollars also rose, buoyed by a recovery in commodity prices and stocks.
(Additional reporting by Jessica Mortimer in London; Editing by Padraic Cassidy)