Slaughter and May and Sidley Austin have both posted 100% retention rates for their autumn intake of newly-qualified lawyers (NQs).

Slaughters is set to keep on all of its 59 trainees in September, marking an increase on recent rounds, after the firm retained 96% of its NQs in March 2011 and 93% in autumn 2010.

Sidley will also keep on all seven of its trainees this autumn, compared with a retention rate of 80% last year, when the firm offered jobs to eight out of 10 of its NQs.

Shearman & Sterling became the first firm in the City to announce its September retention rates earlier this month, with the US firm offering 11 of its 12 qualifying trainees a position, equating to a retention rate of 92%.

In a statement, Slaughters said: "Over the years we have consistently maintained very high retention rates as we seek to recruit for the long term: the retention rate for the upcoming September qualifiers is a clear continuation of that strategy."

The news follows Slaughters decision to increase its associate salaries announced last month opting for modest increases of between 1.5% and 3% for its junior associates.

Meanwhile, Allen & Overy, Linklaters and Herbert Smith are all set to freeze associate pay this year, maintaining their current 2010-11 rates.

Trainee retention rates at the UK's 30 largest law firms rose by an average of 10% in March this year compared with March 2010.