There is a market for vials of processed sperm and for various reasons a sperm bank may sell-on stocks of vials which it holds known as onselling. The costs of screening of donors and storage of frozen donor sperm vials are not insignificant and in practice most sperm banks will try to dispose of all samples from an individual donor. The onselling of sperm therefore enables a sperm bank to maximize the sale and disposal of sperm samples which it has processed. The reasons for onselling may also be where part of, or even the main business of, a particular sperm bank is to process and store sperm rather than to use it in fertility treatments, or where a sperm bank is able to collect and store more sperm than it can use within nationally set limits. In the latter case a sperm bank may onsell sperm from a particular donor for use in another jurisdiction after the number of pregnancies achieved from that donor has reached its national maximum.
Sperm banks may supply other sperm banks or a fertility clinic with donor sperm to be used for achieving pregnancies.
Sperm banks may also supply sperm for research or educational purposes.