The company had total liquidity of $555 million at the end of 2013, compared with $927 million in the previous year, according to the rating agency.
Fitch dropped RadioShack's long-term issuer default rating two notches Thursday to "CC" from "CCC," near the bottom of junk territory. The ratings agency said that it is increasingly likely that RadioShack will need to restructure its debt within the next 12 months.
Shares of RadioShack Corp. fell a penny to $1.33 in afternoon trading. They have fallen almost 50 percent so far this year.