The firm also cut its price target to $85 from $96 on shares of the Hamilton, Bermuda-based parent company of Zales and Kay Jewelers.
Cowen believes the shares will be range bound despite the stock's cheap valuation, the Fly noted.
The firm cited traffic and volatility trends, credit sale uncertainty and the company's fourth quarter risk and reward.
In late August, the stock plunged after the company posted weaker-than-expected results for the 2017 fiscal second quarter and cut its full-year guidance.
Shares of Signet closed slightly higher on Tuesday.
Separately, TheStreet Ratings Team has a "Buy" rating with a score of B- on the stock.
The company's strengths can be seen in multiple areas, such as its impressive record of earnings per share growth, compelling growth in net income, largely solid financial position with reasonable debt levels by most measures, reasonable valuation levels and good cash flow from operations.
Recently, TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this articles's author.
You can view the full analysis from the report here: SIG