The head of the City Council’s finance division will deliver to Mayor Bloomberg’s office today a five-volume budget that includes four significant tax proposals.

The initiatives – and perhaps others that weren’t disclosed in advance – could complicate what otherwise promised to be a smooth negotiation between Mr. Bloomberg and one of the Democrats looking to replace him, the speaker of the City Council, Gifford Miller.

The council’s proposal establishes new taxes for approximately 800 insurance companies, mostly life insurance and casualty firms. It estimates that the new measure will generate nearly $200 million in tax revenue that will allow for other tax decreases.

It is unclear, however, whether Mr. Bloomberg will approve the proposals, given the city’s still precarious fiscal status. A spokesman for the mayor, Jordan Barowitz, said only that the administration would “review” it.

The proposed changes include a 5% across-the-board tax decrease for businesses and a credit for owners of small businesses called “S-corporations,” which currently pay both income and corporate taxes. The council estimates that the former change will provide $160 million and the latter $40 million during their first full year.

The executive director of the Fiscal Policy Institute, Frank Mauro, said he was “surprised” the council would decrease business taxes at all when the city has said it can’t afford to pay a “small part” of new education spending related to a court decision.

A senior fellow at the Manhattan Institute and a fiscal conservative, E.J. McMahon, criticized the new insurance company proposal, saying that pounding that industry has become the “holy grail” for raising taxes.

“The council giveth with one hand and they taketh away with the other,” Mr. McMahon said. “Two-thirds of the package is good. The unfortunate one third is the income transfer from insurance companies.”

Mr. McMahon said imposing steeper taxes on the insurance industry is a move in the wrong direction that comes with potential pitfalls.

“The risk they take is what would this mean for Met Life’s next plan to expand in Long Island City,” Mr. McMahon said.

A spokesman for Mr. Miller, Stephen Sigmund, said the budget closes “a loophole that has allowed one industry to shirk its responsibility for too long.”

The council is also proposing an expansion of the earned-income tax credit for working poor families, to 10% from 5%; hiring 1,000 new police officers, and restoring money for programs financed last year but not made permanent in the budget. That includes money for libraries, which have said they need to scale back hours of operation; for daycare services;, and for senior centers.

Changes to the city’s tax code would have to be approved by the state legislature.

While these changes – and others that will become public today – may cause head-butting, the current budget climate is expected to be less contentious than the atmosphere of the past three years, when the economy was just beginning to recover from the World Trade Center attacks. For one thing, Mr. Bloomberg has already agreed to include an additional $1.3 billion this year to pay for school construction projects. His resistance to doing so was a point Mr. Miller had been exploiting politically.