Business combination transaction costs decreased by $5.6 million to $0.01 million in the three month period ended June 30, 2023, from $5.7 million in the three month period ended June 30, 2022, primarily due to fewer acquisitions entered into in the quarter compared to the comparative quarter.
Impairment of withholding tax receivables increased by $0.4 million to $13.3 million in the three month period ended June 30, 2023, from $12.9 million in the three month period ended June 30, 2022, primarily due to partial reversal of impairment of withholding tax receivables.
Net loss/(gain) on disposal of property, plant and equipment has decreased by $13.4 million to $0.2 million in the three month period ended June 30, 2023, from $13.6 million in the three month period ended June 30, 2022, primarily resulting from a year on year decrease of $13.9 million in our Nigeria segment after completing an assessment of assets verification during the three month period ended June 30, 2022 resulting in a disposal of assets.
Administrative expenses for the six month period ended June 30, 2023 increased by $4.6 million, or 2.4%, which was primarily due to an increase in staff costs (including key management compensation), rent and facilities costs and professional fees, offset by a decrease in net loss on disposal of property, plant and equipment, business combination costs and impairment of withholding tax receivables.
Rent and facilities costs increased by $4.3 million to $21.2 million in the six month period ended June 30, 2023, from $16.9 million in the six month ended June 30, 2022, mainly driven by an increase in repairs and maintenance in Nigeria.
Staff costs (including key management compensation) increased by $14.6 million to $84.8 million in the six month period ended June 30, 2023 from $70.2 million in the six month period ended June 30, 2022, primarily due to increased headcount in our SSA and Latam segments due to the impact of acquired operations in 2022.
Professional fees increased by $11.5 million to $30.0 million in the six month period ended June 30, 2023, from $18.5 million in the six month period ended June 30, 2022, primarily due to an increase in consulting, legal and audit costs.
Business combination transaction costs decreased by $13.2 million to $0.9 million in the six month period ended June 30, 2023, from $14.0 million in the six month period ended June 30, 2022, primarily due to fewer acquisitions entered into in the six month period ended June 30, 2023, compared to the comparative six month period.
Impairment of withholding tax receivables decreased by $3.1 million to $24.6 million in the six month period ended June 30, 2023, from $27.7 million in the six month period ended June 30, 2022, primarily due to partial reversal of impairment of withholding tax receivables.
Net loss/(gain) on disposal of property, plant and equipment has decreased by $14.4 million to net gain $0.6 million in the six month period ended June 30, 2023, from net loss of $13.8 million in the six month ended June 30, 2022, primarily resulting from a year on year decrease of $14.0 million in our Nigeria segment after completing an assessment of assets verification during the six month period ended June 30, 2022 resulting in a disposal of assets.
Loss Allowance on Trade Receivables
We had a loss allowance on trade receivables of $1.0 million for the three month period ended June 30, 2023, compared to a loss allowance on trade receivables of $0.7 million for the three month period ended June 30, 2022, a year-on-year negative movement of $0.3 million.
We had a loss allowance on trade receivables of $4.5 million for the six month period ended June 30, 2023, compared to a net reversal of loss allowance on trade receivables of $1.8 million for the six month period ended June 30, 2022, a year-on-year negative movement of $6.3 million.
Other Income
Other income decreased by $2.8 million to $0.2 million for the three month period ended June 30, 2023, compared to $3.0 million for the three month period ended June 30, 2022. The three month period ended June 30, 2022 includes a non-recurring amount of $2.5 million in relation to a tax indemnity receipt from a seller relating to a prior acquisition.
