38 states: UnitedHealth promises to fix its claims computers and payment systems nationwide over three years under the scrutiny of state insurance regulators. Claims-related penalties hit $18 million, including record fines in four states. Separately, California investigates complaints of claims foul-ups at PacifiCare, an insurer acquired by UnitedHealth.

UnitedHealth Group tripled in size by acquiring other companies since 2000, but insurance regulators in many states found the company often paid medical claims late or not at all -- and didn't do enough when people complained. The problems are rooted in the computers that process claims, regulators say.

Florida: Insurance regulators cite UnitedHealth's claims-handling computers for delays and other payment problems affecting doctors and hospitals.

Ohio, Texas and North Carolina:

Regulators separately blame UnitedHealth companies for payment problems. Fines total $1.3 million.

Missouri: Fresh problems are disclosed with UnitedHealth's claims-payment systems, including overcharging 10,400 HMO members on copays.

Texas, Ohio and North Carolina: Regulators find more claims problems at UnitedHealth. North Carolina imposes a record $2.2 million fine. Ohio blames the company's claims practices for confusion, extra paperwork and unnecessary denials.

Wisconsin, Texas: UnitedHealth pays a record $4 million penalty in Texas and a $600,000 fine in Wisconsin, and is ordered to improve claims handling. Frustrated state insurance commissioners discuss jointly confronting the company.

Arizona, Nebraska, New York, Missouri: Improper denials and other claims problems prompt a record $364,750 Arizona fine. Nebraska regulators allege more than 300 violations of insurance laws. New York stops sending Medicaid patients to UnitedHealth's HMO because of poor claim and complaint handling. A judge in Missouri rules that UnitedHealth's payment systems are flawed.

Source: Financial data from Bloomberg and UnitedHealth Group; regulatory actions from Star Tribune research

Star Tribune

Nebraska: UnitedHealth's claims systems repeatedly deny payment for child oral surgery, in defiance of a state law, prompting complaints and a state investigation.

Each block depicts one company

As it acquired 70 companies, including many health plans, UnitedHealth often had trouble merging claims-payment operations, state regulators found.

*Estimated revenue for 2007; revenues restated for all years except 2000-2001; pending acquisitions in gray.

$20.9 billion* $23.2 billion* $25.8 billion $29.7 billion $38.2 billion $46.4 billion $71.5 billion $75.4 billion*