Seems like wash rule doesn't apply for a similar - but not identical - security. Like maybe Vanguard Total Stock ETF vs SPDR Total Stock ETF. Suppose I buy 5 to 10 sector ETFs. Maybe I make it so they sum up to the total market anyway. At year end, whichever sector ETFs are down, I sell at a loss while simultaneously rotating it to a same sector ETF by a different firm. That way I can claim losses are short-term and reduce tax liability at my marginal rate (surely greater than 15%). On the other hand, for the ETFs that are up, I keep as-is until I'm ready to cash-in. In that case, the tax liability will be fixed at long-term 15%. So this always beats just buying a single total stock ETF? - other than the management required. Does that work out in theory? Is it worth it in practice?