How do i determine investment return required to breakeven when borrowing money?

assume mortgage rate of 6.25%, income tax rate of 38% and investment long-term capital gains tax rate of 15%

One never borrows money to invest. Tell the bank or whom ever loaning the money, it will be invested and the determination of a loan will be 99.9% declined.

Long term capital gains tax rate of 15%? Isn't it more at 28%; then 38%.. Send to IRS for Publication 17 and other investment Pubs it leads you to.

To borrow with expectations of breaking even-----never in a million years. But then again--K-Mart enters bankruptcy---comes out of it and buys Sears----Rite-Aid on the verge of bankruptcy and buys Eckerd and Brooks Pharmacies.

Mortgage rate may be 6.25%, which is a deduction with other deductions to reach over the standard deduction. Your extra income from borrowing, should you find a lender will be wiped out with the 28% capital gains and then the 38% tax bracket.

Suggest you save 9 months of income in a savings account. Then go to a library and research DRIP investing----The purchasing of common stock Directly from most companies, is without the outrageous brokerage fees and even selling is not $50.00, plus $25.00 to verify the transaction, plus $75.00 for calling them between the hours of their working, plus and plus fees for having an account with them.
Reinvesting the dividends in an Investment Program DRIP.

Back to your question: It's the Yield you want not Return; capital gains you are talking about---means you are buying to sell after holding for ---is it one year and a day this year or held for 6 months after a full month when the precipitation is not in excess of 2 inches within a 30 day period following the Hunter's Moon or is it the Harvest Moon, then again perhaps just a regular Full Moon when Congress is not in session to change the calculations you seek.

Hope this makes as much sense as your borrowing money to invest. Why not borrow money and go to a Casino. Then the calculations are easy------Say you borrow $1,000, go to Casino, leave Casino--- the return will be Zero. And you still owe $1,000.