Sky has threatened to shut down Sky News if the news channel proves to be an obstacle in Rupert Murdoch's 21st Century Fox bid.
Regulators are investigating the deal amid concerns that Mr Murdoch's media empire could become too powerful.
Sky told the Competition and Markets Authority (CMA) that the regulator should not assume "the continued provision" of Sky News.
BBC media editor Amol Rajan said it was a "credible threat".
Fox owns 39% of Sky but wants full control of the satellite broadcaster.
In a submission made to the CMA last month, but published by the regulator on Tuesday, Sky said it "would likely be prompted to review" its position if "the continued provision of Sky News in its current form unduly impeded merger and/or other corporate opportunities available in relation to Sky's broader business".
This would particularly be the case if shareholders objected to the merger not happening, Sky said.
Closing Sky News would only be an option of last resort, and the broadcaster would try to find a buyer for the media company before that eventuality, the BBC understands.
Media editor Mr Rajan said that Sky News lost "an awful lot of money".
"It loses tens of millions of pounds, and I think the independent directors of Sky are sending a very clear message... that if they had to choose, maybe they'd prefer for commercial reasons to do the deal with 21st Century Fox rather than continue to fund the losses at Sky News."