William Blair analyst Jim Breen views the 14% pullback in shares of GTT Communications on Friday as a buying opportunity. The analyst understands concerns around the company's recently elevated debt levels to fund the Interoute acquisition, as well as margin weakness and a slight sequential revenue decline in the quarter. The analyst, however, expects GTT to resume organic growth in the second half of the year. Further, with expanding margins and low capital-expenditure requirements, he estimates its free cash flow will continue to increase. Breen keeps an Outperform rating on GTT Communications and notes the Interoute acquisition will nearly double the size of the total company.