Elon Musk's SpaceX is already closing in on Microsoft's market cap and a big Apple milestone

It's blast-off for the newly minted public rocket company SpaceX ( SPCX ).

SpaceX stock is up 9% in premarket trading on Tuesday, indicating an open of above $200 for the first time. At this level, SpaceX would open with a market cap of more than $2.9 trillion.

A $2.9 trillion market cap for SpaceX would put it roughly in line with tech heavyweight and nicely profitable Microsoft ( MSFT ), with a $2.95 trillion market cap, according to Yahoo Finance AlphaSpace data.

What's more, the combined market cap of Elon Musk's SpaceX ($2.9 trillion) and Tesla ( TSLA ) ($1.3 trillion) would be near the $4.3 trillion market cap of Apple ( AAPL ), which is also nicely profitable, unlike SpaceX.

To say it has been a sizzling start for SpaceX would be an understatement.

SpaceX officially priced its stock at $135 on June 11, offering 555.6 million shares. The pricing valued SpaceX at $1.78 trillion.

SpaceX made its historic public debut on the Nasdaq on June 12, when the stock officially opened for trading around midday at $150 per share.

Driven by heavy demand from both institutional and retail investors, the stock steadily climbed throughout the session before closing its first day at $160.95.