Property and casualty insurer Chubb Ltd on Thursday offered to acquire smaller rival Hartford Financial Services Group Inc in a $23.24 billion cash-and-stock deal.

Chubb’s $65 per share offer represents a premium of 13.2% to Hartford’s last close of $57.41.

Hartford earlier in the day said it received a takeover bid from Chubb, but did not disclose the financial details of the offer.

Chubb in its recent statement said it has not yet received a response from Hartford to its proposal, adding that even if a deal is agreed upon, its terms, structure or timing cannot be assured.

A deal between The Hartford and Chubb would be the biggest in the sector since Aon Plc’s $30 billion acquisition of Willis Towers Watson last year, and the largest in the U.S. P&C insurance space since Chubb was created in its current form in January 2016.

Then, ACE Ltd bought Chubb Corp for $28.5 billion, with the combined company retaining Chubb’s branding.

In a note, Wells Fargo analysts called The Hartford’s small-business insurance franchise the main draw for Chubb, which currently focuses on covering mid-sized and large companies. Chubb has around $9.4 billion of excess capital to fund any transaction.

They noted that previous deals in the P&C space valued companies at upwards of 1.8-times book value, likely seen as a baseline for negotiation by The Hartford, which traded at 1.14-times prior to Thursday’s news. A 1.75-times valuation would price The Hartford at $30 billion.

The coronavirus pandemic is reshaping the insurance industry, and consolidation could help cut costs after substantial losses in 2020.

Chubb Chief Executive Officer Evan Greenberg warned in April last year that the pandemic would likely spur the single-largest loss in the industry’s history. The insurer booked $1.19 billion in pandemic-related losses in 2020.

P&C insurers also faced significant catastrophe losses in 2020 from wildfires in western states and the most active Atlantic hurricane season on record. Combined with claims associated with civil unrest, these outweighed benefits from fewer auto claims as people drove less because of the pandemic, Fitch Ratings said in a report on Thursday.

Chubb, which reported $41 billion of gross written premiums last year, also provides personal accident and supplemental health insurance, as well as life insurance, in 54 countries and territories.

Founded in 1810, The Hartford reported $17.3 billion in total premiums last year. The company provides coverage for workers’ compensation, management and professional liability, and other specialized areas, including political risk.

The Hartford famously sold baseball slugger Babe Ruth an insurance policy in 1920 for disability protection and also insured the only home Abraham Lincoln ever owned.

Chubb traces its roots to 1882 when Thomas Caldecot Chubb and his son Percy opened their marine underwriting business in New York City.