The Icelandic striker had previously been linked with a move to West London.
Dutch newspaper De Telegraaf has reported that a deal for around £2.1 million has been agreed between Ajax and French club FC Nantes.
The striker managed 31 goals in 80 appearances for Ajax and is Iceland’s second-top scorer of all-time with 17 goals in 29 appearances.
What next for QPR?
The R’s have made a decent start to preparations for the Championship by re-signing club hero Jamie Mackie.
The 29-year old is an experienced player in England’s second tier and will be a vital addition to Chris Ramsey’s squad as he looks to build a team that can compete.
They now need to add a touch more quality in attacking areas to compensate for Austin’s seemingly inevitable exit. For just over £2 million, Sigthorsson would have represented great value for the West London club but attention must now turn to new targets.