Financial statements N otes to the consolidated financial statements continued 7. Operating expenses 2021 2020 Personnel expenses £000 £000 Wages and salaries 327,653 150,485 Social security costs 42,452 19,015 Defined contribution pension costs 9,045 4,322 Share based compensation 13,876 12,331 Other personnel costs 19,511 18,982 Total 412,537 205,135 The key management personnel comprise the Directors of the Group. Details of compensation for key management personnel are disclosed on pages 71 to 91. Monthly average number of employees 2021 2020 The Americas 3,639 1,537 Europe, Middle East & Africa 1,524 871 Asia Pacific 631 269 Total 5,794 2,677 2021 2020 Other operating expenses £000 £000 IT expenses 16,320 8,132 Consultancy fees 6,161 3,942 Accounting and administrative service fees 5,011 2,577 Operating lease costs 4,448 1,500 Sales and marketing costs 3,713 2,577 Legal fees 3,229 1,801 Travel and accommodation costs 2,318 2,099 Insurance fees 1,807 1,603 Other general and administrative costs 6,822 6,330 Total 49,829 30,561 Impairment losses on trade receivables during the reporting period, amounting to £1.8 million (2020: £2.4 million) are included in general and administrative costs. Subsequent recoveries of amounts previously written off are credited against the same line item. Operating lease costs mainly relate to short term lease costs for land and buildings subject to a practical expedient under IFRS 16. 134 S4Capital Annual Report and Accounts 2021