The hoopla continues over Facebook's initial public offering of stock, which is set for Friday.

The hoopla continues over Facebook's initial public offering of stock, with word that the social media giant has increased the size of Friday's IPO by 25 percent.

According to a statement filed with the Securities and Exchange Commission earlier today, the company now plans to sell 421 million shares — up from the previous estimate of 337 million. According to Reuters, at 421 million Facebook's IPO would be the third largest in U.S. history, after those of Visa Inc. and General Motors.

Tuesday, as we reported, Facebook said it was responding to high demand for the shares with an increase in the expected price, to between $34 and $38 per share from the original estimate of $28 to $35.

If the shares sell at the high end of the new range, Facebook would raise about $16 billion.

As we've also reported, though, it's going to be next to impossible for small investors to get their hands on the stock at its initial offering price — and there's word that General Motors is going to stop advertising on the website because it questions the effectiveness of such ads.

Related posts from our friends at Planet Money:

-- Pizza Delicious Bought An Ad On Facebook. How'd They Do?

-- Is Facebook Worth $100 Billion?

And from Tell Me More: Buying Facebook? Investing 101 For Newbies. [Copyright 2012 National Public Radio]