Global insurance broker, Willis has announced it expects its fourth-quarter earnings to be hit by up to $705 million in non-cash impairment charges.According to an 8-K filing with the Securities and Exchange Commission (SEC), Willis will write down between $450 million and $500 million of goodwill in its North America division related to its takeover of US broker Hilb, Rogal & Hobbs (HRH) prior to the financial crisis.The broker bought out HRH in 2008 for $2.1 billion, which increased Willis’ market penetration in North America but at the same time, weak economic conditions negatively affected its construction and employee benefits business.“As previously disclosed, the North American reporting unit has been hampered by the weakened economic climate and its impact on our acquisition of HRH,” the company stated in the SEC filing.The company said that as of September 30, the goodwill in its North America unit was valued at $1.8 billion.The second charge relates to a change in how the company accounts for and pays its staff bonuses.Until now, some Willis employee bonuses have had a repayment element. If a staff member voluntarily resigned before a specified date, the employees had to pay back a proportionate amount of his or her bonuses.The company would pay the entire award at once, but would only record the amounts that the employee did not have to pay back as an expense. The remainder (the unamortised portion) would be recorded as an asset until the employee had stayed with the company long enough to not have to pay it back.Willis is replacing annual cash retention awards with annual cash bonuses, which will not include a repayment requirement. As a result, the broker will have to pay a pre-tax charge of $205 million, which represents the unamortised balance of past awards.The company’s fourth-quarter results will contain an additional accrual of roughly $250m for these 2012 cash bonuses to be paid in 2013.