The 12-year-old lost out to Scottish singer Jai McDowall in the latest series of the ITV competition, which concluded last month.
The deal with Sony Music sees Syco partner with another of the label departments. Matt Cardle and Olly Murs are among those currently on joint deals between Sony labels.
"Simon is increasingly busy in the US so it makes sense for another of Sony's labels to work on the Ronan Parke project too," a source told The Sun. "It's still to be decided exactly which imprint will partner with Syco but bosses are sure he'll be a success."
However, 24-year-old McDowall remains unsigned. "So far there is no sign of BGT winner Jai McDowall getting a contract," the insider added.
A Syco statement confirmed: "The deal allows Ronan to have Syco's involvement while signing with the Sony team that most suits his musical direction. Simon will remain completely involved."
Parke hit the headlines when an online blogger claimed that the Britain's Got Talent contestant was known to Cowell's company before he competed in the show. Since admitting that he fabricated the claims, the anonymous blogger has been cautioned by police.
> Ronan Parke 'to earn more than Jai McDowall'
> Ronan Parke 'to make £1.5m by Christmas'
Watch Ronan Parke perform on Britain's Got Talent below: