Crypto Position Sizing: How Much to Invest in Each Coin

Most investors spend the majority of their time choosing what to buy and almost no time thinking about how much to buy. This is backwards. A great investment in a 1% position barely moves the needle. A bad investment in a 40% position is catastrophic. The mechanics of how you size positions determine more of your long-term outcome than the quality of any individual pick.

In crypto, this is amplified by the reality that project failure is common — even credible-looking projects with strong teams and real technology go to zero. The 2-5% rule for altcoin positions exists precisely because failure is a real possibility for any given project, and you need the failure to be survivable. If you cannot imagine losing 100% of a position without it materially changing your financial situation, that position is too large.

A practical position sizing framework organizes assets into three tiers based on risk profile. Tier 1 (BTC and ETH): these are your largest positions because they have the highest quality and lowest failure risk. Target 20-40% in Bitcoin and 15-25% in Ethereum, adjusting based on your cycle analysis and overall conviction. Together they should represent 50-70% of your crypto allocation.

Tier 2 (established large-cap altcoins, top 20 by market cap): 5-10% per position. These projects have proven market fit but still carry meaningful risk — ecosystems change, competition intensifies, tokenomics can be unfavorable. Keep positions sized so that a 70% decline does not force you to reconsider your entire portfolio. Tier 3 (speculative and small-cap): 1-3% maximum per position. You expect most speculative bets to fail; a few will succeed dramatically. The math works over time only if losses are small and wins can run.

The Kelly Criterion is a mathematical formula for optimal position sizing: bet the fraction of your capital equal to your edge divided by the odds. In crypto, estimating edge precisely is impossible, but the qualitative principle is useful: the higher your conviction and the better the risk-reward, the larger the position can be — but never beyond the tier limits above.

A simplified version: if you believe a project has a 60% chance of 5x-ing and a 40% chance of going to zero, the Kelly formula suggests risking roughly 28% of your bankroll. In practice, most investors should use a fraction of full Kelly (quarter-Kelly is common) because the formula assumes precise probability estimates we do not have. In crypto, that might mean a 5-7% position rather than 28% — still sized up from the 2% floor, but constrained by the reality of uncertainty.

Even correctly sized positions drift over time. A 5% altcoin position that triples becomes 15% of the portfolio — now dangerously large for the tier. This is not a problem, it is a gift: it means you have a winning position. But managing the drift is important. When a position exceeds 2x its target allocation, consider trimming back to target, or at minimum to a level within your tier sizing rules.

The reverse also happens: losing positions shrink and may no longer justify the attention they consume. A position that has fallen to 0.5% of your portfolio may not be worth the monitoring effort — either average down if the thesis is still intact, or close it and redeploy the capital where you have higher conviction.