Bitcoin Turns 18: What If You Had Invested $100 on Every BTC Birthday Since 2013?

Points of Focus

• Thirteen $100 purchases on every Oct. 31 since 2013 grew to $106,537.
• The oldest four purchases hold 95.3% of the 1.3012 BTC position.
• BTC is down 4.3% in October 2026; the Oct. 31, 2025 purchase is down 25%.

Bitcoin (BTC) turns 18 on Oct. 31, the anniversary of the day Satoshi Nakamoto announced the Bitcoin whitepaper to a cryptography mailing list in 2008. 

A holder who bought $100 of BTC on each Oct. 31 from 2013 to 2025 invested $1,300 and owns 1.3012 BTC, worth $106,537 at a reference price of $81,876, a gain of 8,095.2%.

The oldest four purchases, made at prices between $205 and $729, account for 1.2407 BTC, or 95.3% of the position. BTC has fallen 4.3% in October through Oct. 26, which tests the Uptober pattern on the anniversary itself.

Methodology: This analysis draws on a dataset compiled from Artemis, DeFiLlama, and SoSoValue, with a data cutoff of Oct. 20, 2026. It uses historical daily Bitcoin prices recorded on Oct. 31 each year from 2013 through 2025. Python was used for data analysis and visualization. Please note that the calculations exclude transaction fees, taxes, and inflation adjustments. The results are hypothetical, for illustrative purposes only, and should not be considered investment advice.

Bitcoin at 18: $1,300 in birthday purchases grows to $106,537

The 13 purchases bought 1.3012 BTC at an average cost of $999 per coin, and each is valued at the same $81,876 reference price so that every return shares one endpoint. 

A single $1,300 purchase on Oct. 31, 2013 would have bought 6.34 BTC, worth about $519,214 at the same reference price, so the birthday schedule captured 20.5% of that outcome. At the Oct. 26 daily close of $79,949.93, the position is worth $104,031.

The Oct. 31, 2013 purchase at $205 is worth $39,889, or 399 times its cost, while the 2014 and 2015 purchases are each worth about $25,200. The Oct. 31, 2025 purchase at $109,567 is worth $75, a 25% loss, and that price was 12.1% below the Oct. 6, 2025 record close.

Bitcoin price on every Oct. 31 since 2013

BTC rose 534-fold between the Oct. 31, 2013 price of $205 and the Oct. 31, 2025 price of $109,567. The path included $6,715 in 2017, $61,368 in 2021, and $20,493 in 2022, so a log scale is needed to read it.

A fixed $100 bought 0.48719 BTC in 2013 and 0.00091 BTC in 2025, a 99.8% decline in BTC per birthday. Every purchase is the same dollar amount, so the low early prices carry the portfolio.

The method assumes no fees, taxes, or inflation adjustment.

Bitcoin birthday returns concentrate in the oldest four purchases

The 2013 to 2016 purchases cost $400, or 30.8% of the outlay, and are worth $101,582, or 95.3% of the portfolio. Their returns run from 11,128% to 39,789%, against a median of 795% across all 13 purchases. The 2013 purchase of 0.48719 BTC alone accounts for 37.4% of the portfolio value, and the 2013 to 2015 purchases together account for 84.8%.

The five purchases from 2021 to 2025 cost $500 and are worth $961, a combined gain of 92%. Strategy held 845,050 BTC at an average cost of $75,412 on Aug. 30, 75.5 times the birthday buyer’s average of $999, and the treasury sat 6.0% above cost at the Oct. 26 close. 

The portfolio peaked near $162,000 when BTC set a record daily close of $124,659 on Oct. 6, 2025, so the $106,537 valuation sits 34% below that peak.

Bitcoin’s Halloween Curse: Is Uptober Turning Into a Nightmare Again?

TradingView reports that BTC rose in 10 of the 13 Octobers from 2013 to 2025, with a mean return of 19.9% and a median of 14.8%. The three red months were 2014 (-13.4%), 2018 (-4.5%), and 2025 (-3.9%).

A red October 2026 would make 2025 and 2026 consecutive red Octobers, a sequence absent from that sample, if BTC closes below $83,580 on Oct. 31, a level 4.5% above the Oct. 26 close.

Two birthday purchases show the timing risk: the Oct. 31, 2021 purchase came eight days before the Nov. 8, 2021 record close of $67,526 and returned 33%, while the Oct. 31, 2025 purchase came 25 days after the peak and needs a 37.0% gain from $79,949.93 to break even. 

BTC at $79,949.93 trades 35.9% below the record close, and a close under $70,180 would also put the Oct. 31, 2024 purchase underwater.

Bitcoin price outlook into the 18th birthday close

US-listed Bitcoin exchange-traded funds (ETFs) that hold BTC show $57.25 billion of cumulative net inflows through Oct. 23. 

Flows have swung in October, with withdrawals of $729.0 million on Oct. 7 and Oct. 8, the largest inflow since Sep. 22 on Oct. 19 and a loss of $773.5 million on Oct. 22 and Oct. 23, which brings the birthday price test into the closing week.

Liquidations of $957.12 million on Oct. 15 cleared leverage, and Binance open interest of 93,963 BTC on Oct. 26 sits 0.9% above the 93,131 BTC recorded on Oct. 19. Glassnode put the True Market Mean near $77,000 on Sep. 23, 3.7% below the Oct. 26 close. 

Bitcoin faces $10.89B options expiry as early buyers dominate returns

Deribit options worth $10.89 billion expire on Oct. 30, just one day before Bitcoin’s 18th whitepaper anniversary. The maximum pain level stands at $78,000, approximately 2.8% below the Oct. 26 closing price of $79,949.93.

The timing puts Bitcoin’s birthday at an important market juncture. A close above $83,580 would preserve October’s historical reputation as a bullish month, while a finish below that level would mark the first consecutive red Octobers in the 2013–2026 sample.

However, the birthday investment experiment offers a different perspective on short-term price movements.

Of the $106,537 accumulated through 13 annual purchases, approximately $101,582 came from just four investments made between 2013 and 2016. Meanwhile, the most recent $100 purchase, made in October 2025, remains underwater.

The contrast illustrates how dramatically Bitcoin’s long-term returns have depended on entry prices and holding periods. Investing the same amount every year did not produce equal results, with the earliest purchases accounting for nearly all the portfolio’s value.

As Bitcoin turns 18, the more revealing figure may not be its price on Oct. 31, but the 95.3% of portfolio value generated by its first four birthday purchases. Whether future buyers can achieve anything comparable remains uncertain, particularly as Bitcoin enters adulthood with a vastly larger market and a very different investor base.

Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency prices are highly volatile. Always conduct your own research before making investment decisions.