Why is my tentative minimum tax less than 26% than net alternative minimum tax income?

[doboy0]

My Net Alternative Minimum Taxable Income is 294,426
I expected my tentative minimum tax to be (based on married filing jointly) (114,600 * .26)   (294,426 - 114,600) * .28 = $80,147.28

It shows as $74,962.00

[doboy0]

See image

[RaifH · Accepted solution]

If you have long-term capital gains or qualified dividends, they are taxed at the regular capital gains rate, even for the alternative minimum tax. 

For more information, see Part III of Form 6251 instructions.