Revenue losses from the sale of corporate tax breaks may have already exceeded the entire revenue loss anticipated by the Treasury Department through the end of the 1982 fiscal year.

The extraordinary market in corporate tax breaks created by the 1981 tax bill appears to be exploding as companies face a deadline tomorrow to complete retroactive deals.

"The tax bill has virtually phased out the corporate tax in America," said Roger Altman of Lehman Brothers, a former assistant secretary of the Treasury.

Investment bankers, who are playing key middlemen roles in the sale of corporate tax shelters, said that in just the 90 days since the bill was signed into law on Aug. 13, the revenue loss from consummated deals approaches or even doubles the losses anticipated by the Treasury through next September.

Treasury officials contend that for the entire 1981 and 1982 fiscal years the cost of the controversial section of the tax bill will be $3 billion. If the claims of Wall Street investment bankers are correct, this figure could reach or exceed $6 billion.

For the 90-day period in which companies can sell tax breaks on investments made from Jan. 1 through Aug. 13, Altman's firm estimated that $10 billion worth of equipment had been leased, "an unprecedented amount of private financing of any type" for such a short period.

The Lehman Brothers estimate, which translates into tax losses to the Treasury of about $1.7 billion on deals completed through tomorrow, is, however, one of the lowest in the business.

Analysts at the First Boston Corp. contend that tax sales producing federal revenue losses of $3.6 billion to $6.8 billion will be completed tomorrow. Mary McCue, of the firm, said First Boston has, itself, completed transactions involving in excess of $1 billion in equipment, which translated into tax losses of about $170 million in the first year.

These and other private estimates of the volume of the sale of tax credits and depreciation suggest, if accurate, that the Treasury Department's projection of the total cost through 1986--$29.1 billion--may prove far too small.

The leases completed through tomorrow were accomplished under considerably adverse circumstance because the Treasury revised the regulations as recently as the day before yesterday. In addition, the legal complexities in working out procedures functioned to effectively prevent many smaller firms from participating at the level they are expected in coming months.

Most companies are not publicly announcing their lease deals. This week, however, International Business Machines Corp. said it completed deals with the CSX Corp and B.F. Goodrich Co. Earlier, IBM agreed to buy all of Ford Motor Corp.'s 1981 tax breaks for somewhere between $100 million and $200 million.

Similarly, Ideal Basic Industries, Inc., received $77 million for its tax breaks from a company it declined to identify.

The 1981 tax bill in effect created a massive market in corporate tax breaks by allowing companies with little or no profits to sell unuseable tax credits and depreciation to profitable firms that can take advantage of them. The legislation accomplished this by broadly expanding the definition of leasing to include what amount to paper transactions involving the sale of tax shelters.

The scope of the business is reflected by the claim of Kenneth Lipper, managing director of Salomon Brothers, who said his firm has already signed off on deals "in excess of $2 billion." The $2 billion refers to the value of the equipment involved in the transaction, and translates into a tax loss of at least $340 million.

Peter K. Nevitt, president of BankAmerilease, said he estimated the total volume of leases to be completed by tomorrow's deadline is about $20 billion, which in turn translates into tax losses of $3 billion to $3.4 billion, equal to or more than the amount the Treasury estimated through September 30, 1982, the end of the 1982 fiscal year.