** Shares of online retailer Overstock.com rise 8.7% to $16.3
** JAT Capital Management in a letter to Overstock.com's board has urged a strategic review of the company's non-core assets, most notably its Medici portfolio
** The fund disclosed a 9.1% stake in Overstock.com as of Oct. 12, as per a SEC filing on Monday
** JAT may consider seeking representation on the company's board, if its recommendations are not acted upon, it said
** OSTK shares down 16% YTD
(Reporting by Vedant Vinayak Vichare in Bengaluru)
((vedant.vinayakvichare@thomsonreuters.com))