Strategy estimated a $4.1 billion income-tax benefit on Oct. 5 after Bitcoin's fair market value rose above the company's average acquisition cost as of Sept. 30, according to a regulatory filing with the U.S. Securities and Exchange Commission. The benefit flows from a lower estimated tax expense tied to an internal accounting adjustment.

What the $4.1 billion actually represents

The filing shows Strategy reversed a deferred tax asset linked to its Bitcoin holdings and released the associated valuation allowance. Management-prepared figures drove the estimate; KPMG neither audited nor reviewed them. The company framed the adjustment as limited to its own tax accounts and the September valuation-allowance release, not a restatement of operating results.

Strategy disclosed holdings of 848,000 BTC at an average purchase price of $75,440.70, including fees and expenses, as of Oct. 4 at 4 p.m. Eastern Time. That later acquisition figure carries a separate cutoff from the Sept. 30 accounting comparison used in the tax-benefit calculation.

Why an ETF shareholder faces different math

An ETF's acquisition estimate measures the fund's underlying holdings, not each investor's entry point. Maketo estimated the average cost of Bitcoin remaining in BlackRock's iShares Bitcoin Trust (IBIT) at $81,188 per BTC as of Oct. 2, reconstructing underlying costs from daily money flows and prices.

BlackRock's Oct. 5 holdings file listed about 806,038 BTC. The fund's product page reported nearly $69 billion in net assets and a Bitcoin benchmark level of $85,694.41 that day. IBIT's June 30 quarterly filing recorded 734,261 BTC with an investment cost of roughly $61 billion against a fair value of about $43.4 billion — placing the same holdings below cost at the prior cutoff.

How a shareholder exit actually reaches Bitcoin

An investor can sell IBIT shares in the secondary market. Redemption is a separate channel: only authorized participants can create or redeem baskets directly with the Trust, the prospectus states. Cash redemptions require the Trust to convert underlying Bitcoin into cash, while in-kind redemptions deliver Bitcoin to the participant. The fund's acquisition cost alone leaves the recipient's subsequent decisions unmeasured.

The Trust calculates realized gains and losses on disposals using average cost. During the six months ended June 30, the Trust acquired 157,501 BTC and disposed of 192,970 BTC for share redemptions, including in-kind transfers. The first-half totals leave the timing of those trades relative to cost crossings unresolved.

What the next signal looks like

U.S. spot Bitcoin ETFs recorded net outflows of $89.8 million on Oct. 5, while Farside Investors' data show BlackRock's fund took inflows in the same session. The split captures divergent flow directions across funds in a single trading day.

Establishing whether cost-basis crossings influence those decisions requires comparing flows before and after the crossings over a longer window. Actual creations, redemptions, and the handling of redeemed Bitcoin are the next data points to watch for market impact, ahead of the next quarterly disclosure window that will reveal whether the fair-value gap above the corporate cost basis holds.