NEW YORK (TheStreet) -- Horizon Pharma (HZNP - Get Report) shares have fluctuated between negative and positive territory in early market trading on Monday, after potential takeover target DepoMed (DEPO) announced the adoption of a poison pill plan. The move is to protect DepoMed from any future unsolicited bids for the company.

Last week, Horizon made public its $1.75 billion unsolicited takeover offer for California-based DepoMed, after saying that the drug manufacturer refused to engage in merger talks. 

DepoMed responded to Horizon's offer saying it undervalued the company. Horizon originally put forth its offer in May and has made no changes to it since then.

DepoMed is adopting a poison pill plan that will severely dilute its shares by flooding the market with them if any company acquires more than a 10% stake, DepoMed said today in a security filing. 

Shares of Horizon Pharma are up by 0.17% to $36 in mid-morning trading on Monday. 

Separately, TheStreet Ratings team rates HORIZON PHARMA PLC as a Sell with a ratings score of D. TheStreet Ratings Team has this to say about their recommendation:

"We rate HORIZON PHARMA PLC (HZNP) a SELL. This is driven by a few notable weaknesses, which we believe should have a greater impact than any strengths, and could make it more difficult for investors to achieve positive results compared to most of the stocks we cover. Among the areas we feel are negative, one of the most important has been weak operating cash flow."

You can view the full analysis from the report here: HZNP Ratings Report

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