(Adds details, ATX prospects)
VIENNA, Oct 25 (Reuters) - BAWAG's shares began trading at just below their issue price of 48 euros on Wednesday, valuing the bank at nearly 5 billion euros and gaining entry to the blue chip index in Austria's biggest ever listing.
The former trade union bank had to be bailed out in 2006 when it narrowly escaped a deposit run after being sued by creditors of collapsed U.S. futures trader Refco, which was one of its affiliates.
BAWAG, whose shares opened at 47.40 euros on Wednesday, was then sold to Cerberus Capital Management, and other investors for 3.2 billion euros ($3.8 billion).
The bank is not receiving any proceeds from the IPO, while Cerberus and Golden Tree Asset Management used it to cut their stakes and raise 1.9 billion euros.
With an enterprise value of around 4.8 billion euros and a free float of 39.9 percent, Bawag shares will join the Austrian blue chip index ATX via a so-called fast entry on Friday, the Vienna Stock Exchange said.
This will increase the already high proportion of financials in the ATX index, which tracks 20 stocks.
Erste Group, Raiffeisen Bank International , Uniqa and Vienna Insurance account for nearly a third of the index weighting already.
The Austrian blue chip index has gained nearly 30 percent since the beginning of the year, more than twice as much as the German DAX and largely outperforming its French and British counterparts. ($1 = 0.8505 euros) (Reporting by Kirsti Knolle; editing by Jason Neely and Alexander Smith)