Note 27 Construction contracts

Worked-up not invoiced income

Group, MSEK 2018 2017
Koncernen, Mkr 2018 2017
Worked-up income on incomplete contracts Upparbetade intäkter på ej avslutade entreprenader 36,259 36,733
Invoiced sales on incomplete contracts Fakturering på ej avslutade entreprenader -33,947 -34,325
Total Summa 2,312 2,408

Invoiced income not worked-up

Group, MSEK 2018 2017
Koncernen, Mkr 2018 2017
Invoiced sales on incomplete contracts Fakturering på ej avslutade entreprenader 55,619 45,467
Worked-up income on incomplete contracts Upparbetade intäkter på ej avslutade entreprenader -48,778 -39,215
Total Summa 6,841 6,252

Change in contract balances

2018 2017
Group, MSEK Worked-up not invoiced income Invoiced income not worked-up Worked-up not invoiced income Invoiced income not worked-up
2018 2017
Koncernen, Mkr Upparbetade men ej fakturerade intäkter Fakturerade men ej upparbetade intäkter Upparbetade men ej fakturerade intäkter Fakturerade men ej upparbetade intäkter
Income recognized in the period included in invoiced income not  worked-up at the beginning of the period Intäkt redovisad i perioden som ingick i fakturerad men ej upparbetad intäkt vid periodens ingång 6,252 5,904
Invoiced during the year, reduced by amounts recognized as income during the year Fakturering under året, reducerad med belopp som redovisats som intäkt under året -6,841 -6,252
Transferred from worked-up not invoiced income at the beginning of the period to receivables Överföring från upparbetad men ej fakturerad intäkt vid periodens början till kundfordringar -2,408 -2,688
Worked-up during the year, reduced by amounts invoiced during the year Upparbetning under året, reducerad med belopp som fakturerats under året 2,312 2,408
Exchange rate differences Valutakursdifferenser 29 24 -18 -15
Income recognized during the report period from performance obligations met during previous periods was SEK -330 million (-226).

Worked-up income from ongoing contracts is recognized over time. The degree of recognition is calculated on the basis of the project costs incurred at the end of the period in relation to the project costs corresponding to the project income for the whole project.

Contract assignments are recognized in gross on the balance sheet project for projects, either as Worked-up income not invoiced in current assets or as Invoiced income not worked-up in current liabilities. Projects that have higher worked-up income than the amounts invoiced are recognized as assets, while projects that have been invoiced for more than the income worked-up are recognized as liabilities.