No need to do a double take. Market Vectors, the issuer behind several successful municipal bond ETFs, may introduce a fund with heavy exposure to controversial munis issued by the Commonwealth of Puerto Rico.

A Securities and Exchange Commission filing indicates Market Vectors filed for the Market Vectors Puerto Rico Municipal Index ETF in August, reports Brian Chappatta for Bloomberg.

Jim Colby, a senior municipal strategist at Van Eck, told Bloomberg the ETF could debut later this year or next, depending on feedback from the SEC. Puerto Rico munis have risen to infamy this year as the S&P Municipal Bond Puerto Rico Index is flirting with a year-to-date loss of 20% compared to a decline of around 1% for the S&P Municipal Bond Index.

Puerto Rico, a territory of the U.S., has $70 billion in munis outstanding and those bonds have the lowest possible investment grade rating.  [BlackRock Cautious on Muni Bond ETFs]

The commonwealth’s bonds have rallied since officials gave a webcast briefing for investors on Oct. 15 in which they said the territory has sufficient funding to avoid borrowing before June 30, according to Bloomberg.