Another analyst has weighed in the expected Twitter IPO, and he thinks that it’s going to come sooner than others have predicted.

Sam Hamadeh, CEO of PrivCo, a New York-based private company research firm, says that we can expect Twitter to go public by the end of the year – probably the fourth quarter. He cites a “source high up at Twitter” when making this prediction.

Here’s his rationale:

“By the time Facebook [made its market debut], it had been formally monetizing for four years and its growth rate was slowing,” notes Hamadeh. Meanwhile, if Twitter files to go public at the end of this year, it will hit just the right inflection point, where its revenue is growing in the triple digits, from $80 or $90 million in 2011 to $250 million last year and what we expect will be $500 million in revenue in 2013.”

Basically, Facebook waited too long and Twitter doesn’t want to make the same mistake.

According to Hamadeh, Twitter will price its IPO at $15 billion.

Last week, Greencrest Capital analyst Mas Wolff put Twitter’s valuation at $11 billion, saying that it was up since the Facebook IPO back in May 2012. He said that Twitter would be making preparations to go public this year, and launch the IPO some time in 2014.

Twitter CEO Dick Costolo has been notoriously quick to douse any and all IPO fires that have been lit in the past year or so. He’s made it clear that Twitter was in no rush to go public, and that Twitter needed to be patient in the way they built the business.

[via peHUB]