The Securities and Exchange Commission has launched a formal investigation of Blinder, Robinson & Co. Inc. that focuses on stocks of 16 companies that the Colorado-based securities firm sold to investors.

According to a formal order of investigation dated April 4, 1987, and titled "In the Matter of Blinder, Robinson & Co. Inc.," the SEC alleges that Blinder may have violated securities laws by falsely representing the business prospects for the stocks of companies that it sold to investors.

The SEC document also says Blinder may have falsely represented to investors that certain stocks were new issues when they were already traded, failed to disclose that Blinder was an investor in some of the stocks, sold stocks at excessively marked-up prices, failed to disclose that certain stocks would not be sold upon demand of investors and violated securities laws in other manners.

A subpoena released yesterday as part of the SEC's continuing battle with Blinder revealed that the commission has requested stock trading records and other documents relating to the following 16 stocks sold by Blinder to public investors:

Humbolt Financial, Continental Connector Corp., Continental Industries Inc., Continental Connector Industries Inc., Source Venture Capital Inc., Pierce Ventures Ltd., Telstar Satellite Corp. of America, Kiwi Ventures Ltd., Western International Pizza Corp., Applied Genetic Ventures Inc., Compagnie Equities Ltd., Linc Ltd., De Rosa Foods Inc., AXB Ventures Inc., Prodel Inc. and American Telephone Advertising Holdings Inc.

The SEC has asked for documents concerning trading and other activities in these stocks since Aug. 9, 1983