(Reuters) - American International Group Inc AIG.N executives on Thursday defended their strategy for transforming the company, saying some key improvements would take hold by year-end, but failed to convince investors as shares slid more than 6 percent.

FILE PHOTO: A woman stands in front of an AIG logo in Tokyo March 3, 2009. REUTERS/Issei Kato/File Photo GLOBAL BUSINESS WEEK AHEAD

The New York-based insurer reported a 21 percent decline in first-quarter profit on Wednesday, due to higher catastrophe and bad weather claims, as well as weaker investment income.

“We do expect to deliver an underwriting profit by the end of this year,” said AIG Chief Executive Officer Brian Duperreault in a call with analysts on Thursday.

Duperreault took charge of AIG nearly a year ago, promising to grow the company and boost revenues. He has been working to improve underwriting practices, increase AIG’s focus on technology and install new executives across the insurer to jumpstart profits.

But his steps have yet to boost the bottom line. The stock is down nearly 16 percent since Duperreault’s arrival in May 2017. AIG’s shares were trading at $51.36 on Thursday afternoon after a morning slump during which share were down more than 9 percent.

“Given the results from some other commercial lines insurers in the quarter everyone was expecting a stronger number from AIG, especially in North American commercial business,” said Elyse Greenspan, a Wells Fargo Securities LLC analyst, in an interview.

The unit has been a “consistent area of focus” for AIG and one which the insurer’s former management team was unable to fix, Greenspan said.

AIG’s changes to underwriting practices will take some time to show up in the company’s income statement, said Peter Zaffino, chief executive of AIG’s general insurance unit, during the call. But a combination of managing expenses and improving ratios of losses to premiums will contribute to AIG’s year-end financial performance, Zaffino said.

The company is also making changes to excess casualty business, trying to shed certain risky bets such as being the lead insurer for initial public offerings and professional liabilities, Duperreault said.

AIG also reported on Wednesday that it had released $104 million in reserves from its general insurance unit, the first such development since 2016.

The measure alleviated some investor angst, Greenspan said, after the insurer had to set aside funds in 2016 and 2017 to cover possible future claims.