Facebook today increased the expected share price range for its initial public offering to $34 to $38 a share, according to an amendment to its S-1 filing with the Securities and Exchange Commission. On the high end, the new price range puts Facebook’s market cap over $100 billion.

Previously, the company set a range of $28 to $35, giving it a maximum valuation of $96 billion. Facebook’s initial price range was relatively low considering that company shares went for $44.10 on secondary exchange SharesPost in March. The increased price range suggests there has been significant demand for the stock as Facebook executives met with investors during its roadshow last week. Some reports had said that investors were concerned with how the social network would be able to monetize mobile usage and were showing less interest than expected. Now this does not seem likely to be the case. According to the S-1, underwriters will also sell an additional 50,612,302 shares of Class A common stock to cover over-allotments.

Facebook made another change to its S-1 today indicating that its acquisition of Instagram could be delayed. Previously, the company said the deal would close in the second quarter of 2012, but now it says the deal is expected to close sometime in 2012. This gives weight to reports last week that the Federal Trade Commission would be investigating the deal. An investigation does not necessarily imply wrongdoing, as the FTC regularly reviews acquisitions over $66 million. Facebook bought Instagram for $1 billion. According to the S-1, Facebook has agreed to pay Instagram a $200 million termination fee if for any reason the deal does not close.

Facebook executives are expected to present its IPO pitch to investors in Kansas City and Denver this week. The company is likely to set a final offering price on Thursday before floating the shares on Friday. Some reports say CEO Mark Zuckerberg will ring the Nasdaq opening bell remotely from Facebook’s offices in Menlo Park, Calif.