In June we sold fund shares and made 60K in 2018 LTCG. We have addt'l shares showing a STCL of 25K. Should we sell those now to offset? (Our other joint income is 100K.)

[TaxGuyBill]

Are you asking if you should realize a LOSS $25,000 so you can save $3700 in Federal taxes?

[KKane]

Is there a reason we shouldn't realize the loss in 2018, thereby paying $3750 less in 2018 taxes, and then buy the shares back in a month or so?

[fanfare]

I think his point is it is more valuable to offset LT gains with LT losses, but $3750 is $3750.

[fanfare]

It's a coin flip whether the shares will cost you more or less in February to buy them back.

[fanfare]

You may. That's up to you.
If you want, after the end of January ( 31 days or more) you can buy them back if the price is still the same.

[fanfare]

your sale must settle by Dec 31 to count.

[Anonymous]

wrong it's trade date as reported by brokers

[Anonymous]

In almost all cases, the trade date controls the tax-reporting year for a stock sale. That is, if you sell stock by the last trading day of this year, you report the sale on this year’s taxes. The exception occurs when you close out a short sale for a loss, in which case the settlement date controls the reportable tax year.  

if your fund is in a dividend reinvestment program (DRIP), be very vary of inadvertent wash sales.  for example; say it is in a DRIP. you sell 100 loss shares today.  At year end the fund pays a dividend which is reinvested in 25 shares.  this results in a non-deductible loss on 25 of the shares you sold.  .   

[BobB7]

It's not really non-deductible, it just increases the basis of the 25 shares so the loss recognition is deferred until they are sold. So it doesn't get deducted in the current year.