Tax alpha — the practice of improving investment returns by reducing taxes — has become one of the fastest-growing strategies on Wall Street, according to Bloomberg.  Rather than focusing only on beating the market, many investment firms now design portfolios to minimize taxes, often producing higher after-tax returns even if pre-tax performance is similar to traditional strategies. After years of rising markets, many wealthy Americans hold large unrealized gains in stocks and funds. To address the resulting tax burden, asset managers have developed a wide ecosystem of tax-optimization techniques. More than $1 trillion is now invested in strategies built around tax efficiency, ranging from simple ETF structures to complex hedge fund portfolios. Some of the simplest approaches involve structuring funds to limit taxable events. Certain exchange-traded funds minimize distributions by carefully timing stock sales, reducing investors’ annual tax bills. At the other end of the spectrum are more complex strategies that deliberately generate losses or deductible expenses that can offset gains — and sometimes even ordinary income. One of the fastest-growing segments is tax-aware long-short …