Charter Communications won’t fill the spot on the S&P 500 Index left by its merger partners Time Warner Cable once its deal is completed, a move that according to one analyst could put some short-term pressure on the stock.

JP Morgan media analyst Phil Cusick said S&P’s decision to replace TWC with Digital Realty Trust on the Index could force more shareholders to sell their stock.

In a note to clients, Cusick said that instead of the 10 million shares previously expected to be sold by indexers he expects 32 million shares to be sold by May 17, the expected closing date of the Charter-TWC deal.

In a note to clients Cusick said that could rpresent a buying opportunity for long-term investors in the stock.

“While this does not change our long-term thesis or price target on Charter, it is likely to create significant disruption this week going into the close Friday and removes what we had expected to be a significant driver of near-term performance in Charter shares,” Cusick wrote. “We would recommend fundamental holders buy Charter on weakness as the stock remains our top pick."