GLOBAL MARKETS-Earnings lift stocks but Greek anxiety hits euro

* Adds price updates, changes byline, changes dateline, previous London

* Global equity markets edge higher, Wall Street opens up

* Greece default worries keep investors on edge, hit euro

* Dollar rises for third day in a row

* European stocks up on earnings; U.S. earnings beat low estimates

By Sinead Carew

NEW YORK, April 21 (Reuters) - Global stock markets rose on Tuesday, helped by upbeat European earnings and U.S. earnings that were not as bad as feared, but the euro fell on worries about possible Greek loan defaults.

Wall Street opened higher and European trading was strong, with the pan-regional FTSEurofirst 300 index up 0.93 percent after a 1.4 percent jump by the Nikkei and 2 to 2.5 percent increases in China's main markets. The MSCI gauge of stocks in major markets was up 0.35 percent.

In Europe, Publicis (Paris: FR0000130577 - news) , Sky (Other OTC: BSYBF - news) and ARM Holdings (LSE: ARM.L - news) all rose more than 4 percent after reporting results, with the overall picture of a weaker euro and improving economic conditions driven by the European Central Bank's (ECB) bond-buying program drawing investment into equities.

In the United States, Dow components Verizon (NYSE: VZ - news) , DuPont and United Technologies beat expectations even as the strong dollar weighed on DuPont and UTX. IBM (NYSE: IBM - news) shares were up 0.6 percent after it beat low expectations.

"It's still early in the week, and things could change with some major tech stock reporting later in the week, but there has been the absence of a real negative factor," said Brian Fenske, head of sales and trading at ITG (Shanghai: 600755.SS - news) in New York.

The Dow Jones industrial average rose 12.81 points, or 0.07 percent, to 18,047.74, the S&P 500 gained 4.83 points, or 0.23 percent, to 2,105.23 and the Nasdaq Composite added 28.16 points, or 0.56 percent, to 5,022.76.

The euro was down 0.45 percent at $1.0688 as Greece remained on investors' radar amid media reports that the ECB was considering upping the haircuts it applies to Greek assets used as collateral for its cheap funding.

Even (Taiwan OTC: 6436.TWO - news) after several rounds of negotiations, hopes are slim that Athens will be able to convince euro zone finance ministers to continue their financial support at meetings on Friday. This could mean it runs out of cash by the end of the month.

On Monday, Greece ordered state entities to park spare cash at the central bank in a bid to pay civil service salaries and IMF loan repayments due in early May.

An unprecedented debt default in the currency bloc could open the way for Greece to exit the euro, though ECB Vice President Vitor Constancio said on Monday that a country that defaults would not have to ditch the currency.

"The full extent of a Greek exit (from the euro) is not being priced in," said Grant Peterkin, manager of absolute return bond fund at Lombard Odier.

The dollar gained for a third straight day, trading up 0.32 percent against a currency basket. It is roughly 23 percent higher than it was a year ago.

Oil prices fell as the dollar strengthened. Brent dipped 1 percent to $62.81 per barrel and U.S. crude fell 0.05 percent to $56.30, not far from last week's four-month high of $57.42. (Additional reporting by Tanya Agrawal in Bengaluru, Marc Jones in London, Editing by Shri Navaratnam, John Stonestreet and Meredith Mazzilli)