Catch up on today's top five analyst upgrades with this list compiled by The Fly: 1. Verizon (VZ) upgraded to Overweight from Neutral at JPMorgan with analyst Philip Cusick saying after a meeting with CEO Lowell McAdam, he has a better understanding that Verizon's "organic approach to wireless has the company on an increasingly stable footing." 2. Mosaic (MOS) upgraded to Outperform from Sector Perform at RBC Capital with analyst Andrew Wong saying that it is "hard to ignore the improving undercurrents in both phosphate and potash markets." 3. Ultragenyx (RARE) upgraded to Overweight from Equal Weight at Barclays with analyst Gena Wang saying she thinks a higher price target for Crysvita could drive upside to revenue growth expectations. 4. U.S. Bancorp (USB) upgraded to Buy from Neutral at Citi with analyst Keith Horowitz saying now is an opportune time to build positions in the stock after three years of significant underperformance. 5. AMC Networks (AMCX) upgraded to Buy from Hold at Gabelli with the firm saying it remains an excelling company with opportunities to leverage its recent programming momentum into increased advertising and affiliate fees. This list is just a portion of The Fly's full analyst coverage. To see The Fly's full Street Research coverage, click here.

Ribbon Communications (RRBN) announced plans for a major network modernization program with Verizon (VZ) to retire legacy TDM switching platforms and replace their function with modern cloud-based technologies. Verizon is leveraging Ribbon's portfolio of Voice Products including the vC20 Call Controller, G5 Line Access Gateway, G6 Universal Media Gateway, virtual and Cloud-native Session Border Controllers, and other products which allows for the consolidation and replacement of equipment with energy efficient, software-centric platforms while maintaining full feature functionality.

Wells Fargo lowered the firm's price target on Verizon to $40 from $44 and keeps an Equal Weight rating on the shares. The firm sees encouraging signs in Q1 - improvement in sub trends and limited churn from price-ups - offset by some softness in the business segment and prepaid. Wells would get more constructive when there's visibility on a sustainable improvement in sub trends.