SoundCloud's founders and investors were exploring strategic options for the company, including a sale, that could value it at $1 billion, Bloomberg reported in July.
Both companies are close to completing months of negotiations for deals with record companies and music publishers that will allow them to offer the new services.
The two companies have gone head to head in the battle for music streaming customers since Apple Music was launched in more than 100 countries last year.
In a letter that ran as an advertisement in several publications, the artists claim that the law threatens 'the continued viability of songwriters and recording artists to survive from the creation of music.'