** Shares of medical device maker Cooper Companies COO.O up 6.3% at $76.50 in premarket after reports activist investor Jana Partners has built a stake
** Shares on track for highest level since July 10
** WSJ first reported on Jana's stake, saying the fund could push it to consider combining its contact-lens unit with rival Bausch + Lomb BLCO.TO
** Jana plans to push Cooper to improve capital allocation that could boost returns, sources familiar with the matter told Reuters
** COO down 21.7% YTD
(Reporting by Tharuniyaa Lakshmi in Bengaluru)
((tharuniyaa@thomsonreuters.com))