BFH: company mailbox filing needs no signer-sender identity

A pleading that is only simply signed is validly filed with the fiscal court where it travels the secure route out of a professional practice company's company mailbox (Gesellschaftspostfach)Bundesfinanzhof — even if the Steuerberater who signed it is not the Steuerberater who triggered the sendBundesfinanzhof. In its judgment of 14 July 2026 (IX R 19/25, ECLI:DE:BFH:2026:U.140726.IXR19.25.0), the Bundesfinanzhof (BFH) IX. Senat vacated a Finanzgericht (FG) München judgment that had dismissed a claim as inadmissible for exactly that mismatchBundesfinanzhof, and remanded the case.

The claim reached the FG on 15 April 2025 as an electronic document from the besonderes elektronisches Steuerberaterpostfach (beSt) of the authorised representative, an mbH consultancy company. It carried the scanned signature and typed name of Steuerberater R, entered in the official Steuerberaterverzeichnis. The system note confirmed receipt on the secure route with a vertrauenswürdiger Herkunftsnachweis (VHN); the transfer note showed the send had been triggered by managing director Steuerberater ZBundesfinanzhof under a different SAFE-ID. The FG held the filing failed § 52a Absatz 3 Satz 1 Finanzgerichtsordnung (FGO) for lack of signer-sender identityBundesfinanzhof. The claimant explained that R's identity card had expired and the replacement was not yet activated for the beSt, so Z had performed the authentication step.

§ 52a Absatz 3 Satz 1 FGO offers two routes: a qualified electronic signature of the responsible person, or signature plus filing on a secure routeBundesfinanzhof. The route between a statutory electronic mailbox and the court's office counts as secure under § 52a Absatz 4 Satz 1 Nummer 2 FGOBundesfinanzhof — including the beSt under §§ 86c ff. Steuerberatungsgesetz (StBerG) and the company mailbox for registered Berufsausübungsgesellschaften under § 86e StBerGBundesfinanzhof, which the legislature deliberately qualified as a secure route in the 2021 professional-company law reform so firms could file without qualified signatures.

A simply signed document must in principle be sent by the responsible person themselves — at least from a natural person's personal mailbox, a right the holder cannot transfer. A company mailbox works differently: it belongs to a partnership or corporation, so a non-holder natural person always performs the send. That person must be entitled to represent the company and must themselves be postulationsfähig. The company may grant the send right only to such representative persons practising in the company — the VHN-berechtigte — and only where such a person is logged on at send time does the message carry the VHN confirming secure-route filing.

The court treats the company mailbox like the equally non-person-bound besonderes elektronisches Behördenpostfach (beBPo), where no signer-sender identity is needed either. That distinguishes a simply signing Steuerberater filing through his own personal beSt, where identity with the sender remains required. Measured against that, the FG erred: the pleading was simply signed by R and filed on the company mailbox's secure route with a VHN confirming authorised send by Z. The case was not ready for final decision, though: the FG had never checked the directory entry for whether R was entitled to represent the companyBundesfinanzhof, since a simple signature must also come from a representative Steuerberater or Steuerbevollmächtigter — so München must examine that on remand.

Legal basis: § 52a Absatz 3 and Absatz 4 Satz 1 Nummer 2 FGO, § 55d Absatz 2, §§ 86c ff. and § 86e StBerG, § 13 Absatz 3 Nummer 2 and § 16 Absatz 2 Steuerberaterplattform- und -postfachverordnung (StBPPV); BFH judgment IX R 19/25 of 14 July 2026, vacating FG München 1 K 816/25 of 2 September 2025 and remandingBundesfinanzhof.