The lawsuits filed Thursday in New York State Supreme Court name Lloyd Blankfein and the firm's entire board of directors as defendants.
The suits follow civil fraud charges filed last week by the Securities and Exchange Commission over the same investments.
The SEC says Goldman committed fraud by failing to disclose important information about the securities that might have scared off investors.
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The two suits, filed by shareholders Robert Rosinek and Morton Spiegel, accuse Blankfein and other officers of "systematic failure" over 3 1/2 years for not properly vetting 23 mortgage-linked deals at the center of the SEC suit. Those deals, called Abacus, led to $1 billion in losses.
A Goldman spokesman declined to comment.
The suits appear to be the first shareholder cases related to the Abacus deals. If so, they may mark the start of what legal experts expect will be a flood of shareholder cases against Goldman Sachs.
The plaintiffs seek unspecified monetary damages.
The mortgage-backed securities at the heart of the lawsuits are widely blamed for worsening the financial system's troubles by allowing investors to place massive bets on the direction of the housing market. That triggered major losses at a number of financial institutions after the housing market started to crumble.
As in the SEC case, the shareholders allege that Goldman should have noted in marketing the Abacus securities that a hedge fund betting they would fall in value had helped choose the mortgages on which they were based.
Within a few months of being sold to investors, the value of the Abacus securities fell fast. The hedge fund, Paulson & Co., run by billionaire John Paulson, pocketed $1 billion in profits, the suits says.
Paulson has not been accused of wrongdoing by SEC, and is not as a defendant in the shareholder cases.