Tactical investing involves deliberately overweighting or underweighting certain market segments or industry sectors based on your assessment of market or economic cycles.
Market-capitalization-weighted ETFs offer an efficient way to target the desired tilt.
For example, if you believe that after a protracted period of outperformance by value stocks the pendulum is likely to swing the other way, you might invest in a growth-oriented ETF.
Source: Vanguard. This hypothetical investment or portfolio strategy is shown for illustrative purposes only and shall not be construed as a recommendation to buy or sell any security or financial instrument, or an offer or recommendation to participate in any particular trading or investment strategy.
Points to consider
You could end up doing worse than if you'd made no changes at all.
Whether buying or selling, you would have to be right about the direction of the market/economic cycle, the sectors that might profit from it and the timing of the investments.
Concentration in any security, industry sector, market segment, region or asset class can lead to greater risk relative to a diversified portfolio.