The total carrying value of trade and other receivables was distributed as follows.


December 31,
SEK in millions

20072006
Accounts receivable



Invoiced receivables

13,77112,664
Allowance for doubtful receivables

-729-791
Total accounts receivable at amortized cost

13,04211,873
Currency swaps, forward exchange contracts and currency options held-for-trading

14148
Loans and receivables at amortized cost

5,1626,540
Subtotal (see Categories - Note 27 and Credit risk - Note 28)

18,34518,461
Other current receivables

1,283775
Deferred expenses

1,1591,191
Total trade and other receivables

20,78720,427
TeliaSonera offers a diversified portfolio of mass-market services and products in highly competitive markets, resulting in a limited exposure to individual customers. Reflecting a relatively higher share of post-paid customer contracts, 89 percent of total accounts receivable refer to the operations in the Nordic and Baltic countries. For Accounts receivable and Loans and receivables, the carrying values equal fair value as the impact of discounting is insignificant. Refer to Notes 27 "Financial Assets and Liabilities by Category" and 28 "Financial Risk Management" for more information on financial instruments classified by category and exposed to credit risk, respectively. Loans and receivables mainly comprise accrued call, interconnect and roaming charges.
Total bad debt expenses were SEK 448 million in 2007 and SEK 335 million in 2006 and recovered accounts receivable in these years were SEK 27 million and SEK 36 million, respectively. The allowance for doubtful accounts receivable changed as follows.


December 31,
SEK in millions

20072006
Opening balance

791692
Provisions for receivables impaired

345300
Receivables written-off as uncollectible

-336-88
Unused amounts reversed

-77-106
Exchange rate differences

6-7
Closing balance

729791
The accounts receivable balance includes receivables which are past due as of the balance sheet date, but not provided for as there has not been a significant change in credit quality and the amounts are still considered recoverable. As of December 31, 2007, ageing of past due but not impaired accounts receivable was as follows.


December 31,
SEK in millions

2007
Less than 30 days

2,646
30 - 180 days

843
More than 180 days

1,184
Total past due but not impaired accounts receivable

4,673
Balances past due more than 180 days mainly refer to other operators and distributors. See also section "Credit risk management" in Note 28 "Financial Risk Management" for information on mitigation of credit risks related to accounts receivable.