A major debt service deadline prompts fears that Puerto Rico will default on some of its bonds builds.

According to CNBC, $355 million of notes issued by the Government Development Bank (GDP) will be due on Dec. 1. Money managers, analysts, and investors are anticipating whether the Caribbean island will make difficult decisions to get rid of some of its most senior and constitutionally protected bonds.

The GDB, which is Puerto Rico's financing arm, recently released a finance update indicating the bank's net liquidity is at roughly $875 million as of Sept. 30. The statement also revealed that the bank's cash resources "may be depleted before the end of the calendar year 2015 in the absence of market access, other financing alternatives (including agreements with GDB's creditors) or emergency liquidity measures," CNBC further reported.

Puerto Rico is lacking funds to address its maturing obligations that amount to over $1 billion, CNBC added. This amount is due in the coming weeks, with the island required to decide which debts to pay and to default.

Moody's Investors Service thinks that Puerto Rico will probably default on at least a portion of its debt obligations in the approaching weeks, which marks the island's second default, the news outlet noted.

"The GDB has less incentive to make a payment of $81.4 million of debt service on non-general obligation-backed debt, as the payment pledge does not benefit from constitutional protections," Moody's said in a note issued last week, as quoted by CNBC. "However, given the already severe and growing liquidity challenges facing the commonwealth, it may be forced to default also on the $273.3 million of GDB notes that are backed by the commonwealth's general obligation (GO) guarantee."

Puerto Rico Approves Bill Creating Fiscal Oversight Board

On Tuesday, Puerto Rico's Legislature passed a governor-appointed board to oversee the island's finances, which is aimed to show creditors that its government is dedicated to address spending reforms, Reuters reported.

The fiscal oversight board was proposed by Governor Alejandro Garcia Padilla in an October bill, Reuters wrote. The board, which has five members appointed by the U.S. territory's governor, was passed by both chambers on Tuesday night ahead of the midnight expiration of the legislative session.

Joining the amendments to the bill was "a measure to specify that the board will endorse, rather than approve, the commonwealth's five-year fiscal and economic plan, and will mostly certify, rather than control, fiscal practices," the news outlet added. The bill is also set to implement a financial restructuring at PREPA, Puerto Rico's utility shouldering more than $8 billion of debt. PREPA's management and governance will go through changes as well.