AIG spokesman Chris Winans confirmed receipt of the letter, but not its contents.
The shareholders, who control more than 100 million shares or roughly 4 percent of the company's common stock, in a letter last month asked for a meeting to discuss ways to "improve senior management." That letter did not seek changes at the board level.
In the most recent letter, the shareholders said AIG should form a committee to search for new management.
"This committee should be chaired by a director with strong business experience but one who is also new enough to the board to bear little or no responsibility for the mess created during the last three years," they wrote. "The search process should be formal, thorough and rigorous."
The shareholders also wrote that "it may be expedient" to name a current board member as CEO but added, "If so, this person should only serve on an interim basis."
"Given our long experience and relationships in this industry, we would welcome the opportunity to be of service in proposing or commenting in confidence on possible candidates," the shareholders wrote.
AIG , over the last two quarters, has consecutively posted record losses, largely as a result of $20 billion in write-downs to the value of credit default swaps linked to subprime mortgage investments.