Note 27 Construction contracts

Worked-up not invoiced income

Group, MSEK 2019 2018
Koncernen, Mkr 2019 2018
Worked-up income on incomplete contracts Upparbetade intäkter på ej avslutade entreprenader 36,464 36,259
Invoiced sales on incomplete contracts Fakturering på ej avslutade entreprenader -34,077 -33,947
Total Summa 2,387 2,312

Invoiced income not worked-up

Group, MSEK 2019 2018
Koncernen, Mkr 2019 2018
Invoiced sales on incomplete contracts Fakturering på ej avslutade entreprenader 58,836 55,619
Worked-up income on incomplete contracts Upparbetade intäkter på ej avslutade entreprenader -53,218 -48,778
Total Summa 5,618 6,841

Change in contract balances

2019 2018
Group, MSEK Worked-up not invoiced income Invoiced income not worked-up Worked-up not invoiced income Invoiced income not worked-up
2019 2018
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 6,841 6,252
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 -5,618 -6,841
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 -2,312 -2,408
Worked-up during the year, reduced by amounts invoiced during the year Upparbetning under året, reducerad med belopp som fakturerats under året 2,387 2,312
Exchange rate differences Valutakursdifferenser 14 17 29 24
Income recognized during the report period from performance obligations met during previous periods was SEK -227 million (-330).

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.