Portfolio rebalancing means selling assets that have grown beyond their target allocation and buying assets that have shrunk below theirs. If you start with a 50/50 split between Bitcoin and Ethereum, and Bitcoin rallies while Ethereum stays flat, you might end up at 60/40. Rebalancing sells some Bitcoin and buys Ethereum to return to 50/50. This mechanically takes profits on winners and adds to laggards.
The simplest approach is calendar-based rebalancing, checking and adjusting your portfolio at fixed intervals. Monthly rebalancing is common and works well for most individual investors. Weekly rebalancing captures more of the volatility but generates more transactions (and potentially more taxable events). Quarterly rebalancing is less work but might allow drift to become excessive in fast-moving crypto markets.
Threshold-based rebalancing triggers adjustments when any asset drifts beyond a specified band from its target. If your target for Bitcoin is 40% and your threshold is 5%, you rebalance whenever Bitcoin goes above 45% or below 35% of your portfolio. This approach is more responsive to market moves but requires monitoring. A 5% threshold works well for most crypto portfolios. Tighter thresholds generate excessive trading costs.
The mathematical argument for rebalancing is rooted in volatility harvesting. In a portfolio of volatile assets that are not perfectly correlated, rebalancing captures a rebalancing bonus. By systematically selling high and buying low relative to each other, the rebalanced portfolio can outperform a buy-and-hold approach even if all the individual assets end up at the same price. This effect is larger when assets are more volatile and less correlated, both of which are true in crypto.
The counterargument is that rebalancing fights momentum. In crypto, assets that are going up often continue going up for extended periods. Rebalancing sells into strength, which can reduce returns during strong trends. This is why some traders use asymmetric rebalancing, being quicker to rebalance overweight losers but allowing winners more room to run.
Tax implications of rebalancing matter in many jurisdictions. Every rebalancing transaction that involves selling an appreciated asset triggers capital gains taxes. The cost of these taxes can erode the rebalancing benefit. Strategies to mitigate this include rebalancing through new contributions rather than selling, using tax-loss harvesting alongside rebalancing, and concentrating rebalancing in tax-advantaged accounts where available.
Correlation should inform your target allocations. Assets that move together do not provide diversification benefit. Holding five different Layer 1 tokens that all move in lockstep with Bitcoin is less diversified than it appears. Consider including assets with genuinely different return drivers: Bitcoin, stablecoins or stablecoin yield, DeFi protocol tokens, and perhaps a small allocation to prediction market positions or other uncorrelated strategies.
The implementation matters. Rebalancing in a single large trade can create unnecessary market impact, especially for less liquid tokens. For larger portfolios, consider rebalancing gradually over a day or two. Use limit orders rather than market orders to avoid slippage. And account for transaction fees and potential tax impacts when deciding whether a rebalancing trade is worth executing.
The most important thing about rebalancing is actually doing it. The specific method (calendar versus threshold), the exact targets, and the rebalancing frequency all matter less than the discipline of following your plan consistently. Rebalancing works because it overrides human psychology, which naturally wants to let winners run and ignore losers. The mechanical discipline is the point.