June 26 (Reuters) - Shares of SpaceX rose a

marginal 0.15% on Friday ahead of its inclusion in Russell

indexes, with passively managed funds tracking those benchmarks

required to add billions of dollars' worth of Elon Musk's

internet and rocket company to their holdings.

Traders exchanged about $19 billion worth of SpaceX shares,

with almost half of that turnover in the final minutes of the

session.

After a blockbuster initial public offering this month,

SpaceX's stock has been on a wild ride, soaring 67% to its June

16 intraday high of $225.64 before tumbling to Friday's $153.23

close.

The stock remains well above the $135 IPO price as investors

assess how to value a company that lost $4.9 billion last year,

but that backers expect to dominate the satellite internet, AI

and commercial space launch markets that they believe will

define the next decade of global infrastructure.

FTSE Russell is adding SpaceX to its Russell U.S. indexes after

Friday's close of trading as part of its semi-annual index

reconstitution. That means passively managed exchange-traded

funds that track Russell indexes, such as the iShares Russell

1000 ETF, must add SpaceX shares to their portfolios

before Monday's session.

When new companies are added to an index, passively managed

funds adjust their holdings while trying to minimize the

"tracking error" between their funds' performance and the index

that can result if their buy-in price differs from the closing

price.

While SpaceX's $2 trillion market capitalization makes it

almost as valuable as Amazon ( AMZN ), only about $100 billion

of shares have been listed for trading on the stock market, with

the rest owned by Musk, other insiders and employees.

Passively managed funds need to buy over $4 billion worth of

SpaceX shares to match the Russell indexes they track, according

to a report on Friday from Melissa Roberts, a quantitative

analyst at Stephens.

SpaceX will also be added to the tech-heavy Nasdaq

100 index on July 7, exchange operator Nasdaq confirmed on

Friday, an event that will force large index funds such as the

Invesco QQQ ETF, which tracks that index, to buy its shares.

Following losses in recent sessions, SpaceX is trading at

around 107 times its 2025 sales, an astronomical valuation. By

comparison, AI heavyweight chipmaker Nvidia ( NVDA ) recently

traded at 21 times sales.

S&P Global blocked SpaceX from joining the S&P 500 index

after it said this month it would not change its

inclusion criteria to accommodate megacap IPOs. To ​be included

in the S&P 500, a company must be profitable in its most recent

quarter as ​well as for the sum of its most recent four

quarters, according to one of the rules S&P left unchanged.