A roundup of tech ratings changes

|By:, SA News Editor

American Tower (AMT +1.6%) has been upgraded to Buy by Nomura 10 days after the company announced its $4.8B purchase of Global Tower Partners. Nomura apparently has a different view of the cell tower owner than Muddy Waters.

EZchip (EZCH -1.1%) has been cut to Market Perform by Oppenheimer four days after Cisco unveiled its nPower X1 network processor.

Gigamon (GIMO -3.3%) has been cut to Market Perform by Raymond James.