DETROIT: If a chain is only as strong as its weakest link, Toyota Motor Corp and Honda Motor Co have a problem in the US market directly tied to Detroit’s financial crisis.

General Motors Corp and Chrysler LLC have been pushed to the brink of failure by recent events but the interlocking chain of US parts suppliers means the collateral damage from their collapse will hit Japan’s leading automakers hard. Analysts warn that bankruptcy for either GM or Chrysler could cause a cascade of failures at their suppliers.

That would increase the pressure on better-capitalized Japanese automakers to extend financial aid to keep their production lines running in states from Texas to Ohio, a costly move at a time when auto sales remain down and cash is scarce.

While no automaker would be spared in the shakeout, the deep US presence of Toyota, Honda and Nissan Motor Co make them particularly vulnerable to any supply disruptions, analysts said.

Japanese automakers now represent 40 percent of US auto sales. They also build more than 60 percent of their vehicles sold to US consumers in North America.

In addition, the lean inventory management pioneered by Toyota means that a shortage of a key part could quickly shut an assembly line, analysts have said.

Fifty-eight percent of General Motors Corp’s suppliers and 65 percent of Ford Motor Co’s suppliers also supply Asian manufacturers. By comparison, 37 percent of GM’s suppliers have ties to European automakers.

“There isn’t a supplier out there that does not touch GM,” said Erich Merkle, an analyst at Crowe Horwath. Merkle said GM buys $31bn a year from suppliers, “so when you remove GM, the supply base will file for bankruptcy.”

Merkle and other analysts said a bankruptcy by an automaker would force many suppliers into liquidation because of the near impossibility of finding financing needed to restructure.

“If suppliers liquidate, you won’t have components any more. It’s not just GM, Ford, and Chrysler. It’s Toyota, it’s Honda and it’s Nissan,” Merkle said. The Bush administration is considering emergency aid for the US automakers after a proposed $14bn bailout collapsed in the face of opposition from Senate Republicans.

“Honda and Toyota themselves have started to say if these American automakers start to fail, and fail quickly, it will take out the supply base they all depend on,” said David Kudla, chief executive of Mainstay Capital Management.

Shares of Toyota, No. 2 in US sales after GM, tumbled 10 percent in Tokyo after the bailout talks failed. Honda and Nissan dropped 12.5 percent and 11.5 percent, respectively. “The US auto market is shrinking rapidly,” Toyota said in a statement. “A major bankruptcy would exacerbate an already difficult environment for Toyota and the industry. We hope to avoid this situation.”

Honda and Nissan had no comment. Japan’s automakers account for 13 out of the total 18 vehicle assembly plants in the United States being operated or built by non-US manufacturers.

Hyundai Motor Co and Mercedes Benz both have plants in Alabama. BMW has one in South Carolina. Kia Motors Corp and Volkswagen would be shielded because they import all the vehicles they sell in the United States. Kia is due to open a plant in Georgia in 2009, while Volkswagen is building one in Tennessee.

Foreign-owned plants currently represent about 45 percent of production in North America, nearly double the level at the start of the decade, according to auto consulting firm CSM Worldwide.