The parcel delivery market functions as a complex system, according to the authors of this article. By comprehending and outlining the unique characteristics of the complex system, the authors aim to substantiate their assertion. The Covid pandemic in Hungary's Courier, Express, and Parcel market in 2020 caused a previously unprecedented increase in parcel delivery demands similarly to other countries. The epidemic-related rise in e-commerce additionally resulted significant changes to the approach by which the parcel delivery industry operated. Unexpected collaboration amongst service providers started to emerge on the parcel market in 2021. These alterations are of a kind that suggests the behavioural characteristics of a complex system. Considering that the leading service providers' autonomous operations constitute the primary characteristic of the Hungarian parcel delivery market, an analysis from a scientific perspective of the events that transpired in the Hungarian parcel delivery market is imperative to understand the reasons for this shift. Two research questions have been formulated by the authors, one of which investigates whether the parcel delivery market is considered as a system (complex system), it is conceivable for collaboration to emerge spontaneously if this is the most effective form for the system. The other research question concerns whether cooperation can be established in a market without external interference. To provide an explanation for the developments that transpired between 2020 and 2022, the authors analyse the Hungarian parcel delivery market as a complex system. In complex systems, transformation and self-organization occur naturally when the system decides that a particular shape is best for it in its current environment. During the time under review, the equilibrium of the parcel delivery market in Hungary was disrupted by the unanticipated rise in e-commerce, and the increased demands of customers nearly brought the service providers to a state of chaos. Consequently, the behaviour of service providers started to shift from their previous standards. The article's uniqueness is in its classification of the parcel delivery market as a complex system, which can be used to anticipate the current and expected behaviour of the stakeholders.