* Negotiators hammer out compromise in late-night talks
* Less money to be taken from EU research budget
By Francesco Guarascio
BRUSSELS, May 28 (Reuters) - The European Union agreed on Thursday the final details of a 315 billion euro ($344 billion) plan to boost investment and economic growth in the bloc, opening the way for the first funds to be disbursed in the autumn.
Launched by European Commission President Jean-Claude Juncker late last year, the plan aims to attract private money to help finance projects across Europe that have so far struggled to get off the ground.
Risky ventures will be funded through a new financial vehicle, the European Fund for Strategic Investments (EFSI), that will be backed by an 8 billion euro guarantee provided by the EU budget for the next three years.
Investment in Europe has fallen by a quarter since the 2008 financial crisis but governments, already burdened with huge debts, are in no position to inject money into infrastructure as they seek to keep their budgets in check.
After months of negotiations between the European Commission, EU governments and the European Parliament, negotiators agreed on a compromise in late-night talks to form the basis of a law that will allow the plan to formally start.
One of the obstacles to agreeing legislation was around how much money would come from the EU budget to back the fund's so-called first-loss guarantee, which is designed to attract investors by covering any initial losses should a project fail.
The initial proposal from the European Commission had envisaged that 6 billion euros would come from funds originally destined for research, innovation and infrastructure.
The deal reached on Thursday with the European Parliament and representatives of EU states foresees that cuts to research and infrastructure would be limited to 5 billion euros.
To maintain the EFSI guarantee at 8 billion euros, EU negotiators agreed to tap more money from unused funds of the EU budget, which will now contribute to the guarantee with 3 billion euros, instead of the 2 billion originally planned by the Commission.
The leeway in the EU budget is the result of unspent funds by regions' administrations or may come from fines imposed on companies or states for breaching EU laws.
The EU commissioner in charge of setting up the EFSI, Jyrki Katainen, welcomed the agreement and urged EU leaders and the European Parliament to formally confirm it in June "so we can have the EFSI up and running in autumn."
Parliament is due to vote on the deal on June 24 and EU leaders will meet in Brussels for a regular summit on June 25-26. ($1 = 0.9152 euros) (Additional reporting by Robin Emmott; Editing by Catherine Evans)