Facebook shares slumped further towards their original offering price range in the third day of trading, as scrutiny of the process by which the $16bn offering was brought to market intensified.

The anger among some investors and traders that Facebook did not deliver a “pop” on Friday continued to grow as the stock faced increasing pressure from short sellers looking to bet against its valuation, which had fallen below $90bn as of midday trading yesterday.

The underwriters of the deal, led by Morgan Stanley, were facing questions about why they had increased the size of the deal and raised the price range from $28-$35 to $34-$38 in the days before its offering. The increase came even as analysts were lowering expectations. Analysts cannot publish research about a company their banks are underwriting, but they are allowed have private discussions with investors in the period leading up to an IPO. They reduced their forecasts in mid-May after Facebook revised its prospectus to reflect slowing growth in the first quarter.