"existing rival" is correct and usable in written English.
You can use it to describe a person or organization that has been competing against another person or organization for some time. For example, "The two companies have been locked in an ongoing struggle, with each trying to gain the upper hand over the other existing rival."
If no rival exists, the newcomer encounters a monopolistic market; if one rival exists, then duopolistic competition will occur and in case of more than one, existing rival oligopolistic competition will take place.
The existing rival chain tends to open some new retailers to recapture some income in a near future.
An existing rival is Cryptome, founded in 1996 as a part-time "amateur operation" by John Young and Deborah Natsios, two New York architects with libertarian leanings.
Kagan takes issue with Thucydides' view that the war was inevitable, that the rise of the Athenian Empire in a world with an existing rival power made a clash between the two a certainty.
That government, led by a nine-strong presidency, has yet to set foot in Libya, with the country's two existing rival governments, in Tripoli and Tobruk, both rejecting it.
Sarraj's government has not yet been accepted by either existing rival government in Libya, the Tripoli-based GenerandNathenal CongrelectedC) and tHouse of Representativesesentatines in the eastern part of the country.
Of all Apple's existing rivals, Samsung has made the most inroads with its Galaxy Tab.
I can't overestimate it". This week he described the launch in London and other European capitals as "bringing the digital musical revolution around the world", and he is characteristically bullish about seeing off existing rivals in Britain.
There are existing rivals such as French business Deezer, already available in 182 countries.
For Caffeine, that's a suite of technology products and new experiences that existing rivals don't have.
In the case of Amazon, deep analysis reveals the fundamentals that help the company remain one click ahead of its existing rivals and future competitors.
