Two short stanzas, and a surprising pairing of money talk and intimacy. The title, "Joint stock," borrows the language of business: a joint-stock company is one whose owners share ownership. Here it seems to describe two people who share a life, and the poem treats their closeness almost like a partnership.
In the first stanza, the speaker gives "an account / of my day's work" after love. The word "account" works two ways: it can mean a story told, or a record of money. So the speaker is both telling their partner about the day and, perhaps, settling up. The second stanza moves from talk to bodies: "we join our hips" and enter "the company of sleep." Again there's a business pun, since "company" also means companionship.
The mood is quiet, tender and a little playful. Ordinary work and rest become part of the couple's shared life, and sleep feels like something they enter together.