May 25 (Reuters) - Sweden's indebted SBB on

Saturday entered into a joint venture, SBB Social Facilities,

for approximately 5.7 billion Swedish crowns ($534.36 million)

with U.S. based Castlelake and supported by Atlas SP Partners.

SBB Social Facilities will use loan proceeds to acquire

properties from SBB, to refinance debt to SBB and for certain

external debt, according to the statement.

($1 = 10.6669 Swedish crowns)