In Depth: The Alibaba IPO

Alibaba IPO demand heavily oversubscribed as investors jockey for shares

Strong demand for Alibaba generates $1 billion

Demand for Alibaba's coming initial public offering is so oversubscribed that bankers are expected to close the books to investors in a matter of days, sources told CNBC on Friday.

Orders for the hotly-awaited $21.1 billion IPO—expected to be the largest in historywill close for U.S.-based investors on Tuesday, sources say, with international investors getting their final chance on Wednesday.

Read MoreGood luck getting in on Alibaba IPO

Appetite for Alibaba shares is expected to push the offering price above the current expected range of $60 to $66, these sources added. A whopping 40 large institutions have requested orders over $1 billion, while "friends and family" will comprise about $1.5 billion.

Reporting by CNBC's Kayla Tausche; writing by Javier E. David