In midday trading, GM shares dropped $1.36, or 10.6 percent, to $11.44, after tumbling as low as $11.21 earlier in the session.
The last time the Detroit-based automaker's shares dropped below the $12 mark was on Jan. 2, 1975 when they fell to $11.68, according to the University of Chicago's Center for Research in Security Prices.
Ford shares hit a 52-week low of $4.94 in early trading before recovering to $5 by midday, down 24 cents, or 4.6 percent. They have traded as high as $9.70 over the past year.
GM's drop came after a Goldman Sachs analyst cut his rating to "Sell" from "Neutral" and his price target to $11 from $19, saying things could still get worse for the North American automotive industry as a whole.
"We expect GM shares to continue to underperform as market fundamentals deteriorate which exacerbates liquidity concerns," the investment bank's Patrick Archambault wrote in a note to investors.
"We think GM's automotive cash flow burn this year and next is likely to lead it to look to raise capital, which we believe could lead to significant shareholder dilution and/or a cut to the company's dividend."
"We believe 2Q 08 earnings will likely be weak on the back of prolonged shutdowns at GM and a 22 percent reduction in truck production at Ford," he wrote. "And we believe several companies could revise guidance in the face a perfect storm of volume cuts and commodity cost pressures."
GM shares had traded as high as $43.20 over the past year.
Lear dropped $2.84, or 15.6 percent, to $15.27, easily passing its previous low mark of $16.98. Tenneco shares fell $1.15, or 7.1 percent, to $15.09 after falling as low as $14.89, moving past their previous low of $15.92.
The drops went along with the rest of the market. Major indexes showed losses of more than 1 percent, including the Dow Jones industrial average, which shed more than 200 points and dropped to its lowest level of the year.