Can short term stock loss be used to offset real estate gain? For example, could a $500K short term stock loss offset a $500K real estate gain and pay no taxes?

Yes, but there are limits. Losses on your investments are first used to offset capital gains of the same type. So short-term losses are first deducted against short-term gains, and long-term losses are deducted against long-term gains. Net losses of either type can then be deducted against the other kind of gain.

For additional information please see this TurboTax article, Capital Gains and Losses, which has been updated for Tax Year 2017.

Generally, the capital loss on the sale of the stock can be used to offset the capital gain on the sale of the property.  Generally, you can offsets capital gains with capital losses from any sources. 

unless your investment is bankrupt/wiped out, after 31 days have gone by since selling, you can buy that stock back again. Maybe you'll get some or all of your money back.
It's not easy to lose $500,000 on stock in less than a year.

This sounds like a homework question.

Hello, 

if stock sold was long term loss , could offset some capital gain of house sold? 

Thank you ! 

Rose

 Basically the cap losses and gains are netted against each other on the Sch D  however this  house you sold  ... was this a rental ?