Check out which companies are making headlines before the bell on Friday:
Citigroup - Citi said it experienced interruptions Thursday in the availability of some of its websites. The bank noted that there were no breaches of client data.
Facebook - Facebook's Instagram unit may have lost nearly a quarter of its users after a recent flap over its change in terms of service, according to the New York Post, quoting figures from AppData. Instagram had 16.4 million active daily users the week it rolled out its policy change, but that number has now fallen to 12.4 million, the paper reported.