The line between a [private letter] and a business letter is not easily drawn, but in general the business letter is a document which concerns matters of business and enterprise between private parties, i.e. it does not come from a state office (q.v. [official letter]). It can often concern the management of an estate [888 252 BCE, Philadelphia; 26741 II-III CE] or can be a simple commercial transaction [26937 II CE, Oxyrhynchus]. However, as it can concern business matters between friends and family members, often personal and business matters can be found in the same letter [28136 II-III CE, a father sends many business instructions to his son; 30388 III CE, Oxyrhynchus, concerning a debt payment].
The content varies widely, from financial transactions [677 259 BCE, Beirut (a request for money), 26863 II-III CE, Oxyrhynchus (the return of a deposit)], to agricultural business [888 (the planting of poppies), 27511 II-III CE, Hermopolite nome (when and where to sow crops); 26741 (an instruction to buy crops), 4562 I BCE, Arsinoite nome (sale and transport of grain)]. There is abundant evidence for the purchase of equipment and raw materials [685 258-256 BCE, Alexandria (a boat); 28905 II CE (tripods); 26937 (yarn); 2537 I BCE, Arsinoite nome (flax and copper); 4561 I BCE (transfer of barrels); 30291 III CE (papyrus)], and the collection and payment of goods [17288 68 CE, (collection of threads for a weaver); 30477 III CE, Oxyrhynchus (wine)]. Construction [79425 I-II CE (a house); 31012 III CE, Theadelphia (building site)] and the valuation of property [3083 II BCE] also feature in the corpus. Another letter concerns commercial transactions involving a range of church officials [14264 264-282 CE, Arsinoite nome].
Alongside [private letters], business letters make up a large portion of the corpus and come from every period and all geographic areas. For a full bibliography on ancient letters see [Sarri 2018 : 367-384].For a variation of the business letter see [order to pay].
Other documents with business content are based on a different model, that of the ὑπόμνημα, (hypomnema) and are treated under the type Transmission of Information: sub-type [business note].
The business letter opens with the epistolary introduction [from name <nom.>][to name <dat.>][χαίρειν] [685 258-256 BCE, Alexandria], sometimes πλεῖστα χαίρειν [28702 II CE, Philadelphia], which can be found further extended to πλεῖστα χαίρειν καὶ διὰ παντὸς ὑγιαίνειν ‘very many greetings and good health always’ [21524 1 CE].
Epithets include τιμιώτατος ‘most honoured’ [26741 II-III CE], φίλτατος ‘most beloved’ [21524; 17288]. Kinship terms such as τῷ ἀδελφῷ ‘to (my) brother’  may not always be taken literally, see [Bagnall and Cribiore 2008 : loc. 253].
An unusual opening is found in  κυρίῳ μου ἀδελφῷ… χαίρειν ‘to my lord brother…greetings’, - this is the opening to a Christian letter.
Often personal wishes precede the business of the letter e.g.  where good wishes about a new wife come before matters regarding debt collection and payment. A reference may also be made to the bearer of the business letter, see [Schubert 2022b]
The closing section is similar to that of [private letters], often with a simple [ἔρρωσο]  or ἐρρῶσθαί σε εὔχομαι .[31012; 26929 II CE, Oxyrhynchus]. An epithet may also be added ἐρρῶσθαί σε εὔχομαι τιμιώτατε [27639 II-III CE, Soknopaiou Nesos]; ἐρρῶσθαί σε εὔχομαι, κύριέ μου .
The Christian letter regarding the collection of wine has an extended closing ἐρρῶσθαί σε, κύριε ἄδελφε, ἐν θεῷ πολλοῖς χρόνοις εὔχομαι ‘I pray, my lord and brother, that you remain in good health through many years with God’ .
The development of the format of letters is described in [Sarri 2018 : 87-113]. Business letters surviving from the Zenon archive are predominantly transversa charta [677; 1035; 1038 256-248 BCE, Philadelphia], but there are also Ptolemaic examples in pagina [691 258 BCE, Alexandria, horizontal fibres; 888, vertical fibres], and squarish formats [2537; 4561, both with vertical fibres]. Roman period business letters are found in pagina format [26863; 30477; horizontal fibres], and also in squarish format [27639 horizontal fibres]. A request for a loan is particularly long and narrow [45407 II BCE, Arsinoite nome, (H. 31.8 x W. 6.8cm)].
Many business letters present the text as a single block with no distinction between the sections  or with the closing section indented [677; 685]. Others distinguish the opening [χαίρειν] by indenting it [17288; 26863], or the opening and main text can each be distinguished from the other by the use of ekthesis . The opening address may also be distinguished by a space between it and the beginning of the main text .
A document concerning the repayment of a debt contains two letters on the same sheet ; a letter to Zenon encloses another [4251 253 BCE]. Another letter carries many corrections and may be a draft .
There may be a seal attached .