HGV expanded its portfolio to include Hamburgische Electricitäts-Werke (HEW) and HOCHBAHN AG. It also acquired shares in the aerospace company Messerschmidt-Bölkow-Blohm GmbH (MBB). This was driven by the development of Hamburg as an aviation hub. The stake was sold again in 2002 to refinance the costs of expanding the Mühlenberger Loch site for Airbus. MBB was an early example of HGV's economically motivated investment in a private company.

In October 1979, as a further joint measure, it was decided (as per Hamburg Parliament document 9/1250) to transform the Hamburg gasworks into a HGV (Hamburg Gas and Water Association) company. The background to this was that, following the shift from a production company to a purely distribution company, increasing profits in the gas sector were becoming apparent. Nine years later, the shares in the gasworks were sold to HEW AG, Thüga AG, and Brigitta (BEB) – except for 10.1 percent, which remained with HGV.

Hamburg Waterworks GmbH (HWW) became a new subsidiary within the HGV Group. The establishment of a tax consolidation was intended to avoid the trade capital tax previously levied on the waterworks. Furthermore, the spin-off of the public swimming pool operations from HWW was decided, but these operations remained linked to HWW and thus to the HGV through a tax consolidation agreement. Since the end of 2003, Bäderland GmbH has been a direct HGV subsidiary.

Other publicly owned companies that generated surpluses were incorporated into the HGV group for the purpose of tax optimization. This included Hamburger Hafen- und Lagerhaus AG (today: Hamburger Hafen und Logistik AG, HHLA), which was wholly owned by the Free and Hanseatic City of Hamburg.

Between 1993 and 1995, Hamburg Airport also generated profits and used up previous loss carryforwards. Therefore, in 1996, the idea arose to integrate this company into the HGV network. At that time, the city held a 64 percent stake in Flughafen Hamburg GmbH (FHG) – other shareholders included the federal government and the state of Schleswig-Holstein. At that point, the HGV comprised a diverse portfolio of holdings in the area of ​​public services.

Beer production isn't exactly a government responsibility. Nevertheless, the Hamburg Business Association (HGV) became involved in the late 1990s when Bavaria-St. Pauli Brewery AG ran into financial difficulties. Through the establishment of subsidiaries, the HGV temporarily acquired land to secure the operation of the traditional brewery and the 220 direct and 150 indirect jobs at its Hamburg location.

In 1998, the subsidiaries were successfully sold to Holsten Brewery AG. The HGV's model of acquiring stakes in private companies that are experiencing financial difficulties and are of strategic importance to Hamburg's economy, in order to safeguard the location, has been repeatedly employed since then. Examples include Beiersdorf (2003-2007), Norddeutsche Affinerie (now Aurubis), and Hapag-Lloyd in 2008.

The reorganization of public building management was on the agenda. The introduction of rental payments was intended to achieve improved resource allocation. In addition, opportunities for asset mobilization were to be explored. Land and buildings were transferred to the newly founded limited partnership VHG Verwaltung Hamburgischer Gebäude GmbH & Co. The general partner of this asset management company was established as an HGV (Hamburg Municipal Housing Association) subsidiary. Operating companies were to handle the leasing of the properties.

During this period, the decision was also made to transition the HafenCity area from port-related to urban development. To implement these measures, GHS Gesellschaft für Hafen- und Standortentwicklung mbH (GHS Port and Site Development Company) was spun off from the HHLA Group and integrated into HGV. Simultaneously, the acute budget crisis and the liberalization of the energy market led the city to gradually sell its shares in Hamburgische Electricitäts-Werke AG (HEW).

As early as the mid-1990s, as part of a reorganization of public transport, the corporate structures of Hamburg's transport companies were also restructured. Pinneberg Transport Company (PVG) was spun off from the HOCHBAHN Group and, for competitive reasons, incorporated into HGV as an independent company. Since 2000, Hamburg-Holstein Transport Company (VHH) has also been part of the HGV network. The majority stake in PVG was later acquired by VHH and merged with VHH in 2012.

HGV is expanding its real estate activities and acquiring a 13.75 percent stake in SAGA Siedlungs-Aktiengesellschaft. The aim is to "broaden HGV's real estate expertise and significantly strengthen SAGA's equity base." This expansion coincided with a period of intense public debate about the limits of state economic activity: Despite HGV's recurring profits, proponents of the efficient private-law organizational structure faced off against critics who either raised regulatory concerns based on the state budget regulations or rejected the measures as mere "half-hearted" privatization.

Hamburg adopts principles for the privatization of public companies. The functional model introduced in 1983 is replaced by the so-called responsibility model. The goals were to reduce the density of controls, improve efficiency by avoiding duplication of effort, and strengthen the accountability of the statutory supervisory bodies. As part of this reform, the responsibility of the specialist authorities for managing their holdings was strengthened.

The Finance Authority continued to perform cross-cutting functions and remained significantly involved in important holdings – hence the term "extended responsibility model." The following year, the Senate then classified the HGV's holdings according to the privatization principles. Management – ​​in addition to fulfilling shareholder obligations – is primarily based on state-defined objectives for the public companies and the appointment of Senate representatives to the supervisory boards, who, among other things, decide on corporate strategies and business plans.

Through a squeeze-out, HGV acquired the remaining shares of the minority shareholders in HOCHBAHN AG. Since then, it has held 100 percent of the share capital.

Between 2006 and 2007, Hamburger Hafen und Logistik AG (HHLA) was partially privatized. Following an expression of interest process, 30.3 percent of the share capital was floated on the stock exchange in November 2007 (the port logistics division). The proceeds from this sale—often referred to as the "HHLA billion"—were gradually transferred to the city budget via HGV. In return, HGV acquired further shares in SAGA. Simultaneously, HGV underwent a modernization process, which was formally reflected in 2007 with the renaming of the company from "Beteiligungsverwaltung" (Investment Administration) to "Beteiligungsmanagement" (Investment Management).

At the end of 2008, the TUI Group announced the sale of Hapag-Lloyd AG. HGV intervened to avert a threatened takeover by Asian investors and the feared loss of the Hamburg headquarters. Initially, this was planned only as supplementary support for private Hamburg investors. However, due to necessary support measures in the following years, HGV became the shipping company's largest single shareholder at that time.

Following the referendum on the remunicipalization of the energy networks, HGV initially acquired a 25.1 percent stake in Hamburg's electricity, gas, and district heating companies in 2011. This step was consistently continued with the electricity network at the beginning of 2014, when HGV, through its newly founded subsidiary Hamburg Energienetze GmbH (HEG), acquired the remaining shares from Vattenfall. The repurchase of Gasnetz Hamburg followed in 2016, and Wärme Hamburg in 2019.

HGV presents itself as a large group with over 180 direct, indirect, or associated holdings, total assets exceeding €12 billion, and approximately 20,000 employees.

HGV manages the special fund for school properties in Hamburg. As the owner of buildings and land, the special fund is responsible for planning, constructing, maintaining, and managing school properties according to sound business principles, taking into account the needs of the schools, and leasing them to the Hamburg Authority for Schools and Vocational Training. The project management companies Schulbau Hamburg (SBH) and Gebäudemanagement Hamburg (GMH) are responsible for the construction and management of schools on behalf of the special fund.

Hamburger Energienetze are merging. The merger of the network companies combines the expertise of around 2,300 employees and creates an integrated network operator responsible for supplying approximately 1.4 million households and the Hamburg economy.

HGV is also acquiring a stake in the regional telecommunications company willy.tel GmbH. On June 19, 2024, HGV and willy.tel signed the share purchase and assignment agreement for the acquisition of 49.9 percent of the shares in willy.tel. Together, they aim to further advance the expansion of fiber optic networks in Hamburg starting in 2025.