(Adds background on debt)
Aug 17 (Reuters) - Liquidity at Puerto Rico's Government Development Bank (GDB) has risen to around $1 billion, the commonwealth's chief of staff said on Monday, after dwindling to $778 million as of the end of May.
That was partly boosted by a deal to raise $400 million in Tax & Revenue Anticipation Notes (TRANs), a strict disbursement policy and deposits made by public entities, the governor's chief of staff Victor Suarez told reporters.
However, the commonwealth still needs $400 million to $500 million of new money to operate beyond November, Suarez said.
Puerto Rico's Governor Alejandro Garcia Padilla shocked investors in June when he said the island's debt, totaling $72 billion, was unpayable and required restructuring.
Puerto Rico earlier in August skipped most of the payment on a bond, which GDB head Melba Acosta said reflected "serious concerns about the commonwealth's liquidity."
Suarez added that Puerto Rico would decide in September whether to move forward with a previously announced plan to exchange notes from the GDB. The GDB said in July it may seek to exchange $4 billion of senior notes at below par.
Reporting by a contributor in San Juan; writing by Megan Davies; Editing by Bernard Orr