Building a Global Portfolio

You now have a built portfolio that is spread across geographies with funds chosen deliberately. But a portfolio is never static. If you leave it alone it will drift apart and this chapter is about how to smartly rebalance and correct your portfolio.

Say you built your portfolio around a target split, some in US equities, some in developed and emerging markets beyond it. Markets don't move in lockstep, so after a strong run in one area, your actual holdings no longer match that target. You're now more exposed to whatever just did well, and more vulnerable if it reverses. Rebalancing means selling down the overweight portion and topping up the underweight one, restoring the split you originally intended.

The decision to rebalance is usually the right one. What most investors never think about is what it costs to actually do it.

Every time you rebalance by selling a position, you trigger a taxable event, even though nothing went wrong. A portion of the gain simply leaves the portfolio as tax before it has a chance to keep compounding. This quiet, repeated leakage is called tax churn, and for a global portfolio rebalanced carelessly, it can be one of the largest invisible drags on your long-term return.

The size of the drag depends heavily on timing. You already know that a gain taxed short-term is taxed far more heavily than one taxed long-term. A rebalancing sale made a few months too early, before a position crosses the 24-month line, can cost meaningfully more in tax than the identical sale made just after.

Rebalancing, then, is a genuine trade-off. The cost of rebalancing is the tax you trigger by selling. The cost of not rebalancing is different but critical: the returns your presently underweight position could have earned had it been topped up sooner, and the extra risk your portfolio quietly carries by staying put. Sell too eagerly and tax eats into what you've built. Wait too long and drift itself becomes the risk you were trying to manage in the first place.

Because selling is the most expensive way to rebalance, it should be the last resort, not the first instinct. There's a clear hierarchy worth following, from least costly to most.

The cheapest option is using fresh capital. If you have money still to invest, from an upcoming LRS remittance, say, direct it entirely into the underweight side rather than touching the overweight one. Nothing is sold, no tax event occurs, and the overweight position's holding period keeps accumulating undisturbed, quietly moving it closer to long-term treatment.

Next is redirecting income you're already earning. Dividends are taxable the moment you receive them regardless of what you do with them, so there's no additional cost to steering that cash toward your underweight holdings instead of letting it sit idle.

Only once those options are exhausted should you consider selling, and even then, sell thoughtfully. If you must sell from the overweight side, look first for any underperforming positions within it that can be sold at a loss. That loss can offset gains elsewhere in your portfolio, softening the net tax bill rather than adding to it.

Selling your strongest performers outright, the plain sell-and-buy approach, should be the option of last resort, because it's the one that hands the most value to tax before you've explored any alternative.

Rebalancing isn't something to do reflexively on a fixed schedule regardless of what's actually happened. A calendar doesn't know whether your portfolio has genuinely drifted or just wobbled slightly, and rebalancing when nothing meaningful has changed creates tax cost for no real benefit. The better trigger is a real, noticeable deviation from your target, not a date on a calendar.

It's also worth resisting the urge to trim a position simply because it's grown large. A holding that's outperformed and now makes up a bigger share of your portfolio isn't automatically a problem to fix, sometimes it's simply working. Cutting a strong performer back to its original size purely for tidiness can cap exactly the growth you were hoping for when you bought it.

Rebalancing keeps a portfolio honest about the risk it's actually carrying, but how you do it matters as much as whether you do it. Use fresh capital and existing income before you sell anything, sell losses before winners if you must sell at all, and don't mistake a strong performer for a problem. With construction and maintenance now both covered, the final chapter gathers the mistakes that undo good portfolios even when every individual decision looked reasonable at the time.