We at Insider Monkey have gone over 752 13F filings that hedge funds and prominent investors are required to file by the SEC The 13F filings show the funds' and investors' portfolio positions as of September 30th. In this article, we look at what those funds think of Rubius Therapeutics, Inc. (NASDAQ:RUBY) based on that data. Hedge fund interest in Rubius Therapeutics, Inc. (NASDAQ:RUBY) shares was flat at the end of last quarter. This is usually a negative indicator.