Puerto Rico's ability to meet its financial obligations remains in question, but the island's fiscal problems won't seriously hurt the greater municipal bond market, said Bill Walsh, President of Hennion & Walsh. Walsh said the overall muni market is being boosted by a drop in supply as more municipalities try to lower their debt levels. Meanwhile, demand continues to rise as investors seek safety, yield and tax-free income. Finally, Walsh said investors should own individual issues if possible because they offer greater flexibility and control than exchange traded funds.