How (or is it necessary) to rebalance a 401k with only one index fund?

What percentage of portfolio should be index funds?

The rule stipulates investing 90% of one’s investment capital towards low-cost stock-based index funds and the remainder 10% to short-term government bonds.

How do you balance index funds?

To rebalance, you simply make the appropriate trades to return your mutual funds back to their target allocations. For example, returning to our 5 fund portfolio example, you would buy and sell shares of the appropriate funds to get back to the original 20% allocation for each fund.

Do you need to rebalance index funds?

There’s no right or wrong method, but unless your portfolio’s value is extremely volatile, rebalancing once or twice a year should be more than sufficient.