BY JACOB BUNGE

The Securities and Exchange Commission and the regulatory arm of NYSE Euronext disciplined an equities unit of Goldman Sachs Co. on Tuesday for alleged violations of rules on short selling stocks.

In December 2008 and January 2009, Goldman Sachs Execution Clearing LP allegedly failed to buy enough shares to cover short positions held by customers, according to a notice from NYSE Regulation.

The issue was compounded as the firm continued to accept hundreds of short-sale orders in stocks in which it hadn't obtained enough shares to cover clients' existing short positions