We analyse Stockholm City's fibre access network investment model and its effects on the different stakeholders, and for society at large. Moreover, Stockholm is compared to Copenhagen, which has conditions similar to Stockholm, but where the municipality has not taken an active role in the city's fibre network. The socio-economic return on the fibre infrastructure investment is estimated to over 16 billion SEK, or €1.85 billion at the current exchange rate (nearly three times the investment). This result is based on a few quantifiable effects alone and we expect the actual return to be considerably larger.