If collections fall short, whatever millions are owed will get added to the state's $1.3 billion budget gap.
The biggest chunk owed the state was $2.1 million from a single corporate filer. Stephanie Weyant, a Department of Revenue spokeswoman, said the company has headquarters in New York, but she would not disclose its name, citing "taxpayer confidentiality."
The Philadelphia amnesty program, the city's first in more than 20 years, had collected more than $10 million by Tuesday.
As of December, Philadelphia's single largest tax delinquent was a company called New China Inc., which owed $3.974 million. The corporation owned a downtown surface parking lot that failed to pay some wage, business-privilege, and parking taxes between 1993 and 2001, according to city records.
The principal on that tax debt is $699,000; the rest is interest and penalties.
It was not clear whether New China Inc. had taken advantage of the amnesty. City officials said information on individual taxpayers would not be available until several weeks after the amnesty concludes.
Wai Hung Sze, who is listed in public documents as New China's chief executive officer, could not be located Tuesday.
A lawyer who briefly represented Sze in his tax battle with the city said he did not know where he could be found.
The city and school district are owed $582 million in tax principal, said Joanna Ford, a spokeswoman for the city Revenue Department.
If interest and penalties are included, the amount owed is nearly double that, Ford said. But she noted that penalties would be waived for payers who participate in the amnesty program. They would still owe half the outstanding interest.
How much can be collected is unclear. Delinquent businesses may no longer exist, and individuals may be dead.
District Attorney Seth Williams has vowed to aggressively go after tax deadbeats after the amnesty expires.
The state's heavily advertised program promises to pursue and prosecute scofflaws who fail to pay up by Friday.