Pinsent Masons has nearly tripled its net debt as it increased its overdraft facility by more than £10m, the firm's accounts reveal.

In its accounts for the year to 30 April 2014 the firm reported its net debt had increased from £5.9m on 1 May 2013, to £15.8m at the end of the financial year.

The accounts also showed that a major factor in the rise of net debt was the increase in Pinsent Masons' bank overdraft, which it extended by more than £10m last financial year.

In the 2012-13 financial year the firm had an overdraft of £9.7m, which increased to £20.6m in the 2014 financial year.

Pinsent Masons managing partner David Ryan (pictured) said the group's net debt and overdraft had increased because the firm had made "several investments in people and premises – in particular taking additional space in Paris, Munich, Beijing and Hong Kong" to meet expanding business needs during the year.

He added: "The last several years have been characterised by substantial investment and, while we will continue to invest in growth opportunities, there is also focus on optimising our business and delivering increasing returns from our investments."

The accounts also showed that the top earning member at Pinsents took home £621,739 last financial year, a more than 5% increase on the previous year.

Total staff costs rose from £136m to £146m, an increase of just over 7%.

The firm increased its average number of equity partners by two in 2013-14, bringing its total to 142, while the number of non-equity partners at the firm fell from 191 to 188. As a result, the total number of members at the LLP fell from 331 to 330.

Total fee earner numbers grew from 1,227 to 1,319.

Turnover at firm grew 5% from £306m to £324m and its operating profit grew from £88m to £91m.

From May 2015, financial institutions head John Cleland will take the helm of the firm, taking over from long-standing incumbent Ryan after a contested election for managing partner last December.