"The piracy of electronic audio-visual content is on the rise and posing a huge threat to traditional Pay TV services," it said.
"For example, MultiChoice estimates that more than two million people view pirated versions of the series and movies available on DStv in South Africa.
"Piracy in sports is also pervasive. The reality is that piracy is a further competitive constraint on Pay TV services in South Africa."
However, Icasa said that it wasn't sure how much piracy actually constrained subscription broadcasting as claimed by Multichoice.
"The authority considered the advent of piracy and whether it constrains subscription broadcasting as claimed by Multichoice," it said.
"It came to the conclusion that since there are various efforts to stem the tide of piracy not only in South Africa but globally, it does not offer a strong competitive constraint on subscription television."