Wachtell Lipton Rosen & Katz, Simpson Thacher & Bartlett and Irish pair Arthur Cox and A&L Goodbody have all landed roles as US automotive systems producer Johnson Controls agrees to merge with Ireland-based security systems maker Tyco.

The deal is reportedly worth up to $20bn (£14bn).

Simpson Thacher and Arthur Cox are advising Tyco. The US firm is fielding a team including New York M&A partners Alan Klein and Elizabeth Cooper.

Arthur Cox's team is being led by Dublin corporate partner Stephen Ranalow alongside corporate partners Maura McLaughlin and Geoff Moore.

Wachtell is advising Johnson Controls with a team led by corporate co-chair Andrew Brownstein.  

A&L Goodbody is providing advice on local law aspects of the deal with a team including M&A partners Alan Casey and Ronan Lyons and tax partner Paul Fahy.

Cleary Gottlieb Steen & Hamilton is advising Johnson Controls on global antitrust matters with a team led by Washington based partner Brian Byrne and Brussels based partner Nicholas Levy.

In 2012, Tyco instructed Simpson Thacher and McDermott Will & Emery on its $10bn combination with UK-based pump and valve maker Pentair.

The Johnson merger with Tyco, which will see Johnson's HQ moved to Ireland, will result in at least $500m (£350m) in savings in the first three years, and create at least $150m (£105m) in annual tax savings, the companies said.

There have been a spate of US acquisitions of Ireland-headquartered businesses recently as US companies relocate to exploit the country's lower corporate tax regime – a process known as tax inversion.

Pharmaceutical companies Pfizer and Allergan, which is Irish, record-breaking $155bn (£100bn) deal announced in November has already renewed the debate over corporate tax avoidance.

US Viagra-maker Pfizer would be based in Ireland should the deal be approved.

In July 2015, US company Teva Pharmaceutical's $40.5bn (£26bn) acquired Allergan's generics business. Sullivan & Cromwell acted for Teva while Latham & Watkins advised Allergan.

In March that year, US pharmaceutical company Actavis merged with Allergan. Matheson corporate partners George Brady and Patrick Spicer led the team advising Allergan. Arthur Cox advised Actavis with corporate partner Geoff Moore at the helm.