Cablevision Systems (CVC) was the best performing stock in the S&P 500 on Wednesday, making it TheStreet's Move of the Day. Shares of the cable company soared 18 percent after analysts at Pivotal Research group upgraded the stock to 'buy' from 'hold.' The research firm upped its price target on Cablevision to $31 from $18. Shares currently trade just shy of $25. Cablevision was also boosted after a Reuters report said French cable company Altice SA (ATC) is potentially looking to buy Time Warner Cable (TWC). Sources say the talks are ongoing. Shares of Cablevision have returned 20 percent since the start of the year.