The issues surrounding the initial public offering of social networking giant, Facebook must be reviewed, according to two senior U. S. financial regulators.

The calls for a review have put additional pressure on Mark Zuckerberg-led company, Morgan Stanley, which is its lead underwriter and the Nasdaq stock exchange. The shares of the company closed after falling 8.9 percent to at $31, following an 11 percent fall on Monday.

The company lost more than $19 billion in market capitalization from its $38-per-share offering previous week. The consumer Internet analyst at Morgan Stanley reduced revenue forecasts for Facebook during the days before the IPO. However, the information was not released to the market until the stocks were listed.

Facebook had asked analysts working for some of the 33 underwriters to lower their estimates ahead of the IPO, according to sources closer to the matter. Analysts said that the company did not forecast its figures right and thus asked analysts to revise their analysts.

The company had issued a revised prospectus on May 9 with warnings over the negative impact of users shifting to mobile platforms. Facebook said that it raised $16 billion for itself as well as for its early investors in an initial public stock offering.

The initial public offering, which was expected to value the firm close to $100 billion, valued the social network at about $104 billion, which is more than companies such as Kraft, Walt Disney and McDonald's. It is a big achievement for the company that started eight years ago and had no ways to generate income until recently.