Sidley Austin has increased the salary of all its London associates to at least £100,000 to match Kirkland & Ellis' London rates as it hires a team from its US rival, Legal Week understands.

Sidley currently pays newly qualified associates £90,000, but from 1 May this will rise to £100,000.

Pay for those with one year post-qualifying experience (PQE) will rise from £95,000 to £105,000 while pay for those with two years' PQE will rise from £105,000 to £115,000.

Associates with three years' PQE will see their pay rise £115,000 to £129,000.

The rises are outside of the firm's usual pay reviews, which normally take place over the summer. The current rates were only introduced last September.

Legal Week understands that the trigger for the rise is the arrival of a team of six partners – including four salaried partners and two equity partners – and at least seven associates from Kirkland, news of which first emerged in February. The firm wanted to match Kirkland's pay for the associates joining but did not want to create a two-tier pay system and thus opted to increase all of its associates' salaries in London.

One source close to the moves said that the number of associates making the jump could yet rise to 14.

Before the Kirkland arrivals, Sidley had around 60 associates in London.

It is also understood that the four fixed-share partners and at least seven associates will receive a signing-on fee of up to £100,000 each on top of their salaries.

The fixed-share partners – private equity partner Fatema Orjela, banking partner Bryan Robson, corporate partner Sava Savov and tax partner Oliver Currall – are set to receive the upper end of this range.

The two equity partners joining Sidley as part of the same Kirkland team – London private equity partner Chritian Iwasko and London and Munich private equity partner Erik Dahl – arranged separate pay deals which did not include signing-on fees.

Sidley is set to open a Munich office which will be run by Dahl.

The six-partner team handed in their notice in late February, narrowly escaping Kirkland's new notice period terms. Just a few days earlier high yield partner Andrew Hagan also resigned to join Freshfields Bruckhaus Deringer.

In response to a flood of Kirkland partner exits both in London and globally (some 100 partners have left worldwide since 2014) the firm doubled its notice period in March for outgoing partners.

Equity partners handing in their notice are now held to a 120-day notice period, up from 60 days and the firm also introduced a 30-day notice period for its large salaried partner rank. Previously salaried partners were not held to a notice period or put on gardening leave.

Sidley and Kirkland declined to comment.