Trump's capital gains plan could save Musk billions on Tesla

The Trump administration's capital gains inflation indexing could cut hundreds of millions to billions of dollars from Elon Musk's tax bill on his roughly 700 million Tesla shares, one of the largest personal equity positions in American history.

National Economic Council Director Kevin Hassett has confirmed the indexing measure is part of a broader midterm election tax push, while the Committee for a Responsible Federal Budget estimates the policy could add $170 billion to $950 billion to the national debt by 2035.

Musk's position splits into two very different tax situations. Roughly 413 million shares sit in the Elon Musk Revocable Trust, dating back to Tesla's 2004 Series A when Musk invested about $6.5 million alongside later rounds that brought his cumulative founder-related investment to around $291 million. After two stock splits — 5-for-1 in 2020 and 3-for-1 in 2022, a combined 15-for-1 — the split-adjusted basis on those early shares is exceptionally low. The other roughly 286 million net shares came from exercising 2018 CEO performance options in June at a $23.34 strike price, carrying a basis near the fair market value at exercise, north of $400 a share. With Tesla trading around $325, those recently exercised shares currently show little or no taxable gain.

Cumulative inflation since 2004 runs around 1.77x, and since Tesla's 2010 IPO closer to 1.5x. Applied to the trust's long-held shares, that raises the cost basis and shrinks the taxable gain. But the combined federal long-term capital gains rate — 20 percent plus a potential 3.8 percent Net Investment Income Tax, for roughly 23.8 percent total — applies only to whatever gain indexing leaves on the table. Tesla's stock has compounded hundreds of times over since Musk's earliest investments, dwarfing the 1.5x to 1.8x inflation adjustment.

Where the savings actually land

The phantom-inflation portion of Musk's gain is real, but it's a sliver next to the genuine business appreciation Tesla has delivered. Depending on which basis assumption is used — Musk's exact average cost isn't public, and years of sales since 2021 complicate lot-by-lot tracking — the savings range from low tens to low hundreds of millions on a very low split-adjusted basis of roughly $1 per share, to hundreds of millions or low single-digit billions on higher basis lots from later rounds and options.

For the recently exercised options, indexing does essentially nothing. With a basis near $400 and Tesla trading at $325, there's no meaningful gain to offset. The benefit concentrates almost entirely on the trust's long-held founder shares.

A proposal, not a payout

None of this happens automatically or soon. Republican Sens. Ted Cruz and Tim Scott have pushed similar indexing language, and other lawmakers have urged Treasury Secretary Scott Bessent to implement it through executive action — but nothing has become law. The CRFB's debt estimate invites political resistance regardless of who benefits.

For Musk specifically, most of his position remains unrealized. Existing step-up-in-basis rules at death would already erase the gain for his heirs unless those rules change too. The last time Washington seriously debated inflation indexing was in the 1990s, when the proposal stalled in Congress over revenue concerns — a precedent that suggests the current push faces an uphill path.

Investors should treat this as a data point on how indexing behaves for concentrated, high-conviction founders, not as a signal to reposition around a tax policy that hasn't been written into law. If enacted, the change would disproportionately benefit long-term holders of assets that have appreciated far beyond inflation — a category that includes many tech founders and early venture investors beyond Musk.

This article is for informational purposes only and does not constitute investment advice.