EDIT: I corrected the postpaid subscriptions in that table
Today, DNA’s (Telenor’s result) also came in. With that, we now have information on subscription number development from all operators for Q4. I made the accompanying comparison table, which perhaps sheds some light on why I believe Elisa had a challenging quarter. Unfortunately, DNA/Telenor now only provides the total number of subscriptions without M2M, so its distribution remains subject to my own assessment.

So, at first glance, the situation with total subscriptions might look okay – Elisa’s was quite flat, and Telia significantly increased its number of subscriptions.
Then, looking at Elisa and Telia, M2M subscriptions increased quite a lot for both. For Telia, the increase seemed to be concentrated towards the end of the year, thus gaining market share compared to Elisa. DNA’s M2M subscription numbers are unknown. Based on my experience, the ARPU for M2M subscriptions can be almost anything from cents to euros, but a good average might be a few euros. This is because usage needs vary greatly, from electric cars to industrial automation, with completely different data consumption.
Therefore, it makes sense to remove M2M subscriptions from the comparison anyway, as based on Elisa’s provided data, Postpaid ARPU is €23.60, and mobile ARPU without M2M is around €22.
So, when comparing mobile subscriptions without M2M, Elisa took a hit of -42 thousand, which is over one percent of the entire subscription base. With the ARPU assumption of €22, this has an impact of €22 * 42k = €0.9M on monthly revenue, which amounts to about ten million annually. Since the business is investment-driven, this probably goes almost entirely to the margin…