Harry Styles, Niall Horan, Louis Tomlinson and Liam Payne have reportedly been told to return from their time off for a meeting with the SyCo boss as "issues are still mounting" following Zayn Malik's shock departure from the band last month.
According to the Daily Star newspaper, the boys have been offered a £50 million deal to go on another world tour next year following the release of their upcoming album but are yet to decide whether to agree.
A source said: "Zayn is gone but the issues are still mounting for the remaining four boys. They have been told to return from their time off to tell Simon what they want.
"Promoters have so much buzz for them that they could sell a world tour out three times over. The offer for next year would mean another world tour with bigger stadiums and a £50million deal.
"The four have vowed to finish their current tour and get their material together for the next album.
"But the bigger issue will be what happens next."
While it was recently revealed Louis has plans to set up his own record label - an imprint under Simon's company - both Harry and Niall are also said to have other musical projects in the pipeline, potentially spelling the "beginning of the end" for the band.
The source added: "Harry and Niall both have offers to work on other music projects.
"And many people in the 1D camp think it will be the beginning of the end if the boys turn down something as big as another world tour.
"It would be a massive statement to fans that they are all ready to pursue their own ventures."