Aon Corp. hopes to complete its acquisition of Hewitt Associates Inc. on or about Oct. 1.

Aon, Chicago (NYSE:AON), an insurance broker with a large consulting arm, announced plans in July to acquire Hewitt, Lincolnshire, Ill. (NYSE:HEW), a human resources consulting and benefits administration firm, for about $4.9 billion in cash and stock.

Aon says it and Hewitt still need some regulatory approvals but hope to close on the deal in about a week.

Hewitt shareholders have until 5 p.m. EDT Sept. 29 to say whether they prefer to get paid for their Hewitt shares with cash, Aon stock or a combination of cash and Aon stock. Hewitt shareholders who do not submit election forms will get 0.6362 of a share of Aon common stock and $25.61 in cash per Hewitt share.