Kidder, Peabody & Co., one of the 10 largest investment firms in the world, yesterday was censured by the Securities and Exchange Commission for failing to take "reasonable steps" to ensure the accuracy of statements involved in two equity purchase deals.

The commission also voiced "concern" over the firm's failure to warn other underwriters, or to inform the SEC, of suspected manipulation of a 1972 stock offering by the Giant Stores Corp. (a firm not related to Giant Food Inc. of Washington).

As a result of these findings, the commission ordered Kidder, Peabody to adopt procedures to guard against similar legal violations. It is also ordered the firm to deposit $40,000 in a special account, to be disposed of in a play yet-to-be proposed.

Without either admitting or denying the allegations, Kidder, Peabody consented to the SEC's findings that the firm "willfully violated" federal securities laws and agreed to adopt the safeguards spelled out by the commission. The firm also agreed to deposit the $40, 000 as directed - the amount being compensation Kidder, Peabody received for underwriting one of the questionable offerings.

In that case - a 1971 offering of 518,000 shares worth of $8.5 million of Fisco, Inc., an insurance holding company - the commission charged Kidder, Peabody had failed to exercise "that degree of healthy skepticism . . . required of an underwriter engaged in a public offering." Had the brokerage firm been more skeptical of the information being supplied by Fisco, "it would have been able to discover that Fisco had been misinforming it," the SEC order stated.

"(Kidder, Peabody) was presented with information which should have caused it to question Fisco's statements and to investigate the accuracy thereof," the order said.

According to the SEC, the alleged misrepresentations resulted in an understatement of Fisco's loss reserves. The SEC claimed Kidder, Peabody "did not attempt to independently ascertain the basis of such reserves or their adequacy" - in particular, it failed to contact an outside insurance company which was having a dispute with Fisco about the accuracy of reserves.

Also, the stock prospectus failed to disclose that the Gateway Insurance Co. - a wholly owned subsidiary of Fisco - had recently acquired more than $13 million in policies from an outside insurance company.

In a second case - this one involving a 1970 offering of limited real estate units worth about $2.2 million - the SEC again said Kidder, Peabody should have gone further in checking certain facts.