Facebook is planning to file IPO registration papers next Wednesday, according to the The Wall Street Journal. Few additional details so far, except that Morgan Stanley (MS) is expected to be lead underwriter with Goldman Sachs (GS) “also likely to play a major role.

[Update: WSJ is now hedging a bit on that specific date, saying that “timing is still being discussed.”]

The social network would be looking to raise around $10 billion at a valuation of between $75 billion and $100 billion. That would make Facebook the largest tech IPO of all time, so long as you exclude telecom companies like AT&T Wireless ($10.62 billion in 2000). There also were a pair of foreign telecom companies — Germany’s Deutsche Telekom and Australia’s Telstra — that priced larger IPOs in the U.S.

Overall, a $10 billion offering would be the seventh-largest IPO ever to price on a U.S. exchange, and the largest since General Motors (GM) raised over $18 billion in November 2010.

An investment banking source tells Fortune that he also has heard rumors about Facebook filing next week, but was unable to confirm. A company shareholder adds that the WSJ report “makes sense to me.”

The report is sure to get Silicon Valley hyperventilating, since Facebook is expected to be the largest tech IPO of all time. But it’s worth remembering that speculation about this deal has been rampant for months, and there have been more than a few false alarms.

Earlier this week was a report about how Facebook had temporarily halted secondary trades of its private shares for a three-day period, causing some to expect the filing to come in that window. It didn’t happen, with trades expected to resume on Monday.

Just yesterday, we engaged in the same guessing game, based on Facebook COO Sheryl Sandberg agreeing to speak at a Harvard Business School event in May. If Facebook files next Wednesday, our assumption was incorrect. If it doesn’t, then the waiting game just continues.

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