Facebook will likely leave it to investors to decide if it’s a $100-billion company.

The social media giant is preparing to sell shares to the public for the first time and could file initial public offering documents as early as Wednesday, setting the stage for what will be one of the most discussed and debated market debuts in the history of Wall Street.

The share sale will likely be led by Morgan Stanley, whose bankers are considering pegging Facebook’s value below the $100 billion mark — a stratospheric valuation that is typically reserved for blue-chip companies like Apple, Exxon and McDonald’s.

The notion that the Silicon Valley darling may not be quite at that lofty level is acknowledged even within Facebook, said sources familiar with the company’s IPO plans.

Bankers are dealing with a range between $75 billion and $100 billion, according to WSJ.com, which would set the share price between $31 and $42.

Analyst Sam Hamadeh of Privco.com, a private-company research firm, yesterday said that Facebook’s share price would be between $38 and $40, leaving post-IPO market cap just shy of $100 billion.

That scenario would grant some room for a first-day pop and allow investors to decide whether Facebook’s valuation belongs in more rarefied territory.

Facebook, founded by Harvard dropout Mark Zuckerberg, has become one of the most ubiquitous companies since Google, boasting some 900 million users, with 80 percent coming from outside the US, according to Facebook’s own data.

As first reported by The Post, Facebook already has reserved “FB” as a possible ticker symbol that it could use on either the Nasdaq or the New York Stock Exchange.

Facebook is leaning toward tapping Morgan Stanley for the plum assignment of lead underwriter — a big diss to rival Goldman Sachs, which stumbled in marketing a private auction of Facebook shares a year ago. Neither bank would comment.

A win by Morgan Stanley would be a huge coup for its head of tech banking, Michael Grimes, who has been leading the charge to score the Facebook listing.

Although offerings on the scale of Facebook are a rarity, Morgan Stanley could fetch a commanding 60 to 70 percent of the fee pool as lead underwriter, sources said. That would leave what’s expected to be an army of secondary underwriters to fight over the scraps.

Not being tapped to lead the Facebook deal would be a big blow to Goldman’s tech investment bankers, who have been smarting over the perception that they’re playing second fiddle to Morgan Stanley on a number of notable tech IPOs in the last year.

Almost a year ago, Goldman was considered to be a shoo-in to lead Facebook’s IPO after the bank was tapped to sell a private offering of some $1.5 billion shares of Facebook.

Goldman became swept up in a public relations fiasco after media coverage of the deal drew scrutiny from the Securities and Exchange Commission, which questioned whether the offering had run afoul of securities rules.

According to several sources, the embarrassing fumble never truly sat well with Facebook’s executives. Given the size of Facebook’s IPO, however, Goldman could end up taking a more active role in the deal and wind up with a bigger cut of the fees.