Those who thought that record low of US $19.69 which Facebook sank to on Nasdaq earlier this month was a buying opportunity were wrong, Facebook’s stock hit a new low of US $18.03 after analyst firm BMO Capital Markets cut its price estimate on the company’s shares from $25 to $15 today.

Bank of America-Merrill Lynch and Bank of Montreal slashed their targets on Facebook by 34% and 40%, respectively, Research firm eMarketer also just announced that it expects Facebook’s revenue for this year will remain under the company’s previous estimates. eMarkteter now predicts that Facebook’s ad revenue will reach $4.23 billion for 2012.

“We expect investor attention to return to fundamentals after the technical challenges presented by lockup expirations over the next six months have been absorbed by the stock,” said BMO analyst Daniel Salmon “Valuation is underpinned by revenue growth, and we believe flat 3Q sequential growth would be met with a step down.”