After the fall in Apple’s stock value when the China Mobile failed to materialise as expected on 18th December, yesterday’s news that the deal had finally been concluded sent the stock shooting back up again, having climbed more than 3 percent at the time of writing (it was up 4% in pre-market trading but has settled).

With the WSJ having reported that 18th December was the day, the market was clearly jittery when nothing materialized. Everything had appeared to be in place: regulatory approval, Apple putting the handsets on sale in China on the opening weekend, China Mobile posters, a pre-order website, in-store displays – and 4G service up-and-running on schedule … 

One theory suggested that China Mobile wanted to renegotiate its volume breaks with Apple after seeing far greater demand for the iPhone 5s than for the cheaper 5c, while Fortune suggested this morning that perhaps Apple wanted to delay the deal until supplies had caught up with demand elsewhere, and that China Mobile had been applying none-too-subtle pressure on Apple by announcing the date as if it were a done deal.

Either way, there will be a lot of relieved faces that the deal has finally been signed, and Apple can look forward to a bumper quarter once the handsets go on sale in January.