Greek debt restructuring inevitable -State Street

* Ireland one global slowdown away from default

* EU must "sign check" to tackle sovereign crisis

By Cecilia Valente and Tommy Wilkes

LONDON, May 12 (Reuters) - A Greek debt restructuring is inevitable and recovery estimates of up to 60 cents a euro are optimistic, the global head of fixed income at State Street Global Advisors said on Thursday.

"We might actually think that in some cases the 50 to 60 cent (on the euro trading) price is optimistic... there may be a greater need for restructuring," Kevin Anderson, who leads a team running $375 billion in fixed income assets, said.

State Street (STT.N), the world's third largest institutional investor, stopped investing in Greek sovereign debt last June after many sovereign debt indices excluded the country's debt.

Anderson said Greek sovereign bonds are currently in "limbo" because they have dropped out of most developed market indices and do not classify as emerging market debt either.

Greece is waiting to find out if it will get the fifth aid instalment from a 110 billion euro ($153.7 billion) bailout offered by the European Union and the International Monetary Fund last year. [ID:nLDE74B0YY]

Without the next 12 billion euro tranche, Greece would default. The IMF and EU officials are also considering more favourable terms to avoid a debt restructuring. [ID:nLDE74B0B5]

State Street is also underweight in the debt of Portugal and Ireland, while keeping neutral on Spain, which Anderson said is unlikely to "be tipped over the edge" into default.

LUCK OF THE IRISH?

State Street's Head of Fundamental Equity Chris Johns, who joined the firm following its purchase of Bank of Ireland's funds unit in January, said Ireland had a 30 percent chance of servicing its debt without defaulting. [ID:nLDE69L0MF] [ID:nLDE73C15Z]

"I would say that we are probably one cyclical slowdown away from a default. All bets are off in the periphery if over the next couple of years ... an unexpected shock causes a global slowdown," Johns said.

And European authorities will fail to resolve the crisis so long as they try to fix the problem by lending money rather than giving it to the countries in need, Johns said.

"Ultimately I think the markets are saying this has to end with a cheque being written. Solvency is about somebody giving somebody money not somebody lending some money," he said. ($1=.7158 Euro) (Editing by Sinead Cruise and Alexander Smith)