Amid calls for disclosure of more information on bidding for auction-rate bonds after dealers stopped buying the securities, two economists told BloggingStocks Friday that the problem of a lack of investor demand speaks directly to the need to re-capitalize bond insurers MBIA and Ambac.

"The problem is not merely a lack of demand for bonds. The problem is that institutional investors are shunning these investments because they are concerned about a lack of available insurance for this debt and related credit market uncertainty, which underscores the need to address the liquidity concerns of MBIA and Ambac," economist David H. Wang said Friday.

MBIA, Ambac: two linchpins

The bond insurers, Wang said, are two linchpins of the bond market [municipal, corporate], and, by extension, of the financial markets.

Shares of MBIA (NYSE: MBI) and Ambac (NYSE: ABK) have lost more than 70% of their value in the past six months, as investors have fled them amid concern that the two do not have sufficient capital to fund insurance policies for mortgage-backed and collateralized debt obligations held by banks and institutions. MBIA and Ambac executives have rejected the accusations, arguing that they have sufficient capital to fund claims and can modify/improve their business models, long-term, aided by re-capitalization. MBIA fell 80 cents to $11.82 and Ambac fell 45 cents to $10.08 in Friday afternoon trading.