Its third Charity Audit Spotlight report found there are 893 audit firms advising the UK’s largest charities. The findings suggest growth in audit fees is slowing down year on year. Previous years have seen increases of 4.4%, 4.3% and 3.8%, while last year’s total spend was £65.6m.

It says while auditors may be offering better value, fee levels will also be affected by the makeup of the charities being audited, and increasingly low levels of inflation may have had an influence.

The most expensive audit for a charity with income under £1m was once again the Congregational and General Charitable Trust, which had an audit fee of £38,000 followed by the Dutch Oak Tree Foundation, which had an audit fee of £30,000.

The most expensive audit overall was for the Wellcome Trust, which paid £600,000 to PwC, up from £500,000 the previous year

One third (33%) of the top 5,000 charities experienced an increase in audit fees, 48.4% saw no change, and 16.8% saw a decrease. The percentage increase is greater for the higher income bands, meanwhile fees generally stayed the same for the lower income bands.

There were 28 charities that had an income greater than £80m with audit fees of more than £100,000. Conversely, there were 731 charities with income less than £1m with audit fees between £1000 and £5000.

Crowe Clarke Whitehill (CCW) still leads the table for receiving the most in audit fees from the top 5,000 charities, with fee income of £5.6m. Second is PwC earning £4.7m. BDO retains the third place  it gained in 2014 with fee income currently £4.37m, with RSM ranked fourth at £4.3m. Grant Thornton is fifth, with £3.6m in fees, and KPMG is sixth with £3.5m.

Last year, Kingston Smith took ninth position from Deloitte but the Big Four firm has now regained this slot with £2.7m of audit fees, moving Kingston Smith back down to tenth at £2.5m.

The largest movement in the table is the position of Smith and Williamson which last year was at 24th position but are now ranked 16th. The top 10 firms collectively earned £37.5m in fees, up from £36.8m last year, which represents 55.8% of all top 5,000 charity audit fees.

RSM (previously Baker Tilly and RSM Tenon) still has the most clients in the sample with 244 top 5,000 charities on its books, although this figure is down from 287 according to data relating to 2010/11.

The firm nevertheless retains a 4.9% market share but CCW and Haysmacintyre have nearly closed the gap and only four clients are all that separate the top three firms. RSM is followed by CCW with 241 clients, while haysmacintyre has 240 (up from 226) and BDO has 210 (down from 213). Buzzacott remains in fifth with 174 (up from 171).

PwC audits the largest amount of charity income – a total of £5.78bn, up by 5.1% on the £5.5bn it held in the previous year. It has held this top ranking for the past five years, helped by large clients such as Cancer Research UK (£634.9m income), the National Trust (£494.1m) and Wellcome Trust (£438.7m).

CCW comes second in the list with £4.58bn. Its largest clients include the Academies Enterprise Trust (AET, £274.3m), Oasis Charitable Trust (£271.7m) and Oasis Community Learning (£192.8m).

Charity Financials highlights the fact that 42% of charities have never changed auditor over the last decade, suggesting that they are missing opportunities for more competitive services. Its data on changes over the past 14 years shows that among those that have switched auditor, 37% have changed once and 17% have changed twice, while 206 charities have changed three or four times. Only two organisations changed five times.

The largest charity to change auditor was Marie Stopes International which paid a fee of £247,000 to PwC when it previously paid £319,000 to CCW, while Haysmacintyre made the most client gains over the latest year examined in this report.

The Charity Financials report is available here