* Accelerated bookbuilding runs until Wednesday
* Parent RZB committed to 750 million euro order
* Rights issue to follow
* Proceeds to boost balance sheet, repay state aid (Adds details and background)
VIENNA, Jan 21 (Reuters) - Austrian lender Raiffeisen Bank International (RBI) is aiming for a 50 percent boost to its share capital through the sale of 97.5 million new shares to investors and existing shareholders, the bank said on Tuesday.
At Tuesday's closing price of 29.90 euros, that would represent a deal worth about 2.9 billion euros ($3.93 billion), exceeding the 2.25 billion that central and eastern Europe's second-biggest lender had said it could raise to beef up its balance sheet and repay state aid.
The sale kicks off a year of capital raising by European banks keen to convince regulators and investors that they are robust enough to weather any more financial storms.
RBI said majority owner Raiffeisen Zentralbank (RZB) had agreed to waive all of its subscription rights and committed to participate in the bookbuild offer with a 750 million euro order.
RZB, itself owned by regional banks, now has a 78.5 percent stake in RBI and has said it wants to keep a majority holding.
The bookbuilding process for institutional investors is set to run until Wednesday, while a subsequent rights issue for existing shareholders would run from Jan. 24 to Feb. 7, the bank said in a statement.
If all the new shares are placed and based on the Jan. 20 share price of 30.50 euros, RBI would reach a core equity Tier 1 capital ratio of about 9.9 percent of risk-weighted assets, easily complying with the Basel III global banking accord.
RBI will use proceeds to redeem non-voting participation capital it raised in 2009, starting with the state tranche. "RBI plans to redeem any remaining portion of the participation capital within the course of 2014," it said.
Raiffeisen received 2.5 billion euros of such capital to help it to ride out the financial crisis, with Austria providing 1.75 billion euros and private investors the rest.
Deutsche Bank, Raiffeisen Centrobank and UBS are joint global coordinators and joint bookrunners. Barclays, BNP Paribas, Commerzbank, ING, and Intesa are acting as co-lead managers for the offering. ($1 = 0.7383 euros) (Reporting by Michael Shields; Editing by Anthony Barker and David Goodman)