(Reuters) -Arthur J Gallagher will buy insurance broker AssuredPartners in a $13.45 billion all-cash deal, it said on Monday, as it deepens focus on property and casualty and employee benefits across the U.S.

The deal will expand Gallagher's offerings in niche segments, including transportation, energy, healthcare, government contractors and public entity, and bolster its business in the UK and Ireland.

The Insurer, a Reuters publication, exclusively reported on Sunday that Gallagher was close to a deal for AssuredPartners.

Gallagher said the deal's net consideration was about $12.45 billion, reflecting about $1 billion deferred tax asset. Shares of the Illinois-based company dipped 0.3%.

Private equity firm GTCR - which founded AssuredPartners in partnership with industry veteran Jim Henderson - said the deal was the largest sale of a U.S. insurance broker to a strategic acquirer in the industry's history.

AssuredPartners distributes insurance across property and casualty, commercial, employee benefits and personal lines. It generated $2.9 billion in adjusted revenue for the 12 months ended Sept. 30.

GTCR initially owned AssuredPartners from its inception in 2011 till 2015, when it sold the Florida-based company to private equity firm Apax Partners.

In 2019, an investor group led by GTCR agreed to acquire it from Apax, which retained a minority stake in the company.

Gallagher had the opportunity to compare notes with AssuredPartners last year, its Chief Financial Officer Douglas Howell told analysts.

At one point, AssuredPartners decided it wanted to do an initial public offering, Howell said, adding that the deal came back on over the last six weeks with no investment bankers involved.

MIDDLE-MARKET EXPANSION

The deal will deepen Gallagher's footing in the commercial middle-market space, where it has operated for nearly a century.

Gallagher follows in the footsteps of rivals Aon and Marsh McLennan, which have struck $13 billion and $7.75 billion, deals, respectively, over the last year to expand into the vast and fast-growing middle-market insurance business.

The broad U.S. footprint and middle-market focus of AssuredPartners make it an ideal merger partner, Gallagher CEO Patrick Gallagher said in a statement.

Middle-market insurance caters to mid-sized businesses that generate annual revenue between $10 million and $1 billion.

"We're going to hand them tools, in particular in the data and analytic world, and they're going to make them incredibly stronger in their local communities, which is where we see tremendous growth," Pat Gallagher said in an interview with Reuters.

Gallagher expects to finance the transaction through a mix of cash, debt and equity. Separately, it unveiled an $8.5 billion stock offering to fund the acquisition and secured a $13.45 billion short-term loan.

The deal, which is expected to boost Gallagher's adjusted profit by double digit, is anticipated to close in the first quarter of 2025.