September 1, 1981

Confusion prevailed among banks and thrift institutions after an I.R.S. warning that it might not permit tax-free incentives for the new ''All Savers'' certificates. Many of the institutions, pending a final decision, suspended the packages, which are sold through a high-interest-bearing repurchase agreement. Those that did not require an automatic rollover into a savings certificate dropped their advertising but continued to sell the packages. (Page A1.) Six-month money market certificates may be converted into the new ''All Savers'' certificates Oct. 1 without any early withdrawal penalty, Federal banking regulators ruled. The decision opens the way for the potential conversion of nearly $500 billion of the popular money market certificates. (D19.)

One man was killed and at least four persons were hurt yesterday morning when two adjoining four-story brick tenements collapsed in a racket of falling debris and clouds of dust behind the Port Authority Bus Terminal. Both of the buildings, on the west side of Ninth Avenue just north of 41st Street, were more than a century old. One of them, No. 571, apparently collapsed first and pulled down the second one, immediately to the south, at No. 569. A two-block section of the avenue was sealed off as a result of the collapse, causing extensive traffic jams through the afternoon on the West Side of Manhattan.

After years of ambitious spending and aggressive acquisition, Tiger International has closed in on its goal of providing a complete door-to-door cargo transportation service using truck, rail and aircraft. But there are a couple of big hurdles yet to clear. One of the problems is Purolator Inc., which is resisting Tiger's attempts to acquire its courier service. Another is Reliance Group Inc., which has 19.5 percent of Tiger's stock.

The Customs Service is testing its ability to prosecute those who import antiques and artifacts that are claimed by other nations as part of their cultural heritage. The service is seeking indictments in a case involving more than $1 million worth of gold, silver, pottery and other pre-Columbian artifacts from Peru. If successfully prosecuted, the case could set a legal precedent empowering the Customs Service to interdict shipments of cultural materials as ''stolen property,'' on the basis of foreign laws declaring that the materials belong to foreign governments. A Federal grand jury in Alexandria, Va., is investigating the case, which involves a New York art dealer and others, according to persons familiar with the details. The case raises a thicket of complex issues involving international relations and international law, scholarship and business.

Banks and savings and loan associations across the country reacted in confusion yesterday to an Internal Revenue Service warning about their high-interest ''bonus'' programs aimed at lining up deposits for the new ''All Savers'' certificates. In a survey, many savings and loan associations said they were shelving the packages while they awaited a final I.R.S. ruling, expected this week. Other savings institutions and commercial banks said they were revising their pro- Chase Manhattan and First National of Chicago cut their prime rates half a point, to 20 percent. Page D1. grams in an attempt to meet what they believed were the IRS objections.