The tax-exempt market could also see pressure due to "heavy issuance, anemic flows, and rate volatility," according to Barclays PLC.

Nelson Pérez Méndez will become the interim Secretary of the Treasury.

S&P`s outlook revision to positive means there is a one-in-three chance the state could have its AA-plus rating upgraded to AAA over the next two years.

The firm settled charges with FINRA over failing to include the Non-Transaction Based Compensation indicator for 91,059 reports of municipal securities transactions over a five year period.

When it comes to sectors, Miller said he likes charter schools, healthcare, land-secured debt and some industrial revenue bond positions.

The Chicago Board of Education on Wednesday saw its issuer rating and debt ratings from Moody`s Investors Service elevated a notch to Ba1 from Ba2.