Yes if the gain is a lot you should send in an estimated payment. Either send in a 1040ES voucher
<a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/f1040es.pdf">https://www.irs.gov/pub/irs-pdf/f1040es.pdf</a>
Or pay directly at <a rel="nofollow" target="_blank" href="
https://www.irs.gov/payments">https://www.irs.gov/payments</a>.
