Claims by four of Wall Street's main market makers against Nasdaq over Facebook's botched IPO are likely to exceed $100 million, as they and other traders continue to deal with thousands of problems with customer orders.

A technical glitch delayed the social networking company's market debut by 30 minutes on Friday and many client orders were delayed, giving some investors and traders significant losses as the stock price dropped. The exchange operator is facing lawsuits from investors and threats of legal action from brokers.

Four of the top market makers in the Facebook IPO - Knight Capital, Citadel Securities, UBS AG and Citi's Automated Trading Desk - collectively have probably lost more than $100 million from problems arising from the deal, said a senior executive at one of the firms.

Knight and Citadel are each claiming losses of $30 million to $35 million, potentially overwhelming a $13 million fund the exchange set up to deal with potential claims.

Nasdaq also has to contend with the outside prospect that it could lose the Facebook listing entirely after having just obtained it.

Facebook shares ended regular trading on Thursday up 3.2 percent at $33.03, about $5 short of their offering price. Action on the stock, however, has essentially become secondary to the fallout from the IPO -- its price, its size, its execution and questions about selective disclosure of its financial prospects.

Regulators including the US Securities and Exchange Commission, the Financial Industry Regulatory Authority and Massachusetts Secretary of the Commonwealth William Galvin are now looking into how the IPO was handled. The US Senate Banking Committee is also reviewing the matter.