Mercury Systems (MRCY) Stock Rises 10% on JANA Stake Build-Up Posted byZacks Equity Research December 24, 2021 Leave a comment on Mercury Systems (MRCY) Stock Rises 10% on JANA Stake Build-Up Buying a 6.6% stake in Mercury Systems (MRCY), JANA Partners intends to discuss strategic alternatives with the company’s management, including a potential sale of the business.