I'm afraid I'm missing something because the 0% tax bracket for capital gains seems too good to be true.
Everything I'm reading (e.g. "The zero percent tax rate on capital gains applies to people in the 15 percent marginal tax rate or below. In 2018, that applies to married tax filers with taxable income up to $78,750, and single tax filers with taxable income up to $39,375." at thebalance.com) says that my capital gains tax rate is dependent only my income tax bracket.
In other words, say I have $2 Million worth of a mutual fund, which I bought more than a year ago for $1 Million (i.e. long-term capital gains of $1 Million). If my income this year is $40,000 and I sell all holdings in this fund, I will pay $150k of capital gains tax. However, if my income is $38,000 and I sell it all, I pay nothing.
Is this correct? If not, what am I missing?