Robo-Advisor Rebalancing Lab

A robo-advisor's core job isn't picking stocks — it's deciding when to trade a drifting portfolio back to its target mix. This simulator runs stocks, bonds and cash forward month by month under random market returns, letting each asset's share of the portfolio drift away from its target weight, then applies whichever rebalancing policy you choose: never, on a fixed calendar, or only once a drift-band threshold is breached. Watch the three bars snap back to their target band on every triggered rebalance, and compare the algorithm-managed portfolio's value, trading costs and tracking error against a buy-and-hold portfolio that never corrects at all.