According to several sources, the Perseus Books Group has completed negotiations over new e-book terms with Amazon. The agreement covers not only Perseus’ own imprints, but the more than 400 independent publishers that use the company’s Constellation service for e-book distribution.

Perseus would not comment on the report, but sources with knowledge of the deal confirmed that the publisher and e-tailer have come to an agreement on the matter.

Reached for comment, Amazon declined to discuss its deal, or negotiations, with Perseus. And, as an indication of how sensitive these type of negotiations are, sources said Amazon insisted that Perseus communicate the news to its clients over the phone, rather than via email.

That Amazon would reach new e-book sales terms with Perseus, as the e-tailer continues a protracted and much-covered impasse over terms with Hachette, will certainly raise eyebrows and bring questions. The big question, as some sources noted, is what e-book terms Perseus agreed to with Amazon, that Hachette has not, and will not.

NOTE: This story has been updated form its original version to reflect new developments.