In a year that offered both optimism and challenges, we continued to navigate the ongoing pandemic to deliver on our promise to our members.
In 2021, despite another year of uncertainty in the global markets, we successfully managed the Plan through the turbulence to exceed our investment targets. It was another strong year for the Plan, with a net investment return of 8.9%. The portfolio grew from $8.0 billion to $8.5 billion, owing to the positive investment returns over the year, particularly in the fourth quarter of 2021. Net investment return for the five-year period ending Dec. 31, 2021, was a solid 8.6%, and the Plan’s 10-year track record continued its long-term trend, earning 9.3% to exceed our benchmark return of 8.4%.
At TTCPP, ensuring the long-term sustainability of the Plan is at the foundation of everything we do. With this commitment in mind, the Investment team in 2021undertook an asset and liability study to assess the long-term sustainability of the Plan. Informed by this study, we made slight adjustments to our portfolio to increase long-term target allocations to infrastructure and credit investments. We believe these modifications will position us to continue meeting our pension obligations well into the future and to withstand any challenges that might lie ahead.
Ensuring the sustainability of the Plan also means hiring the right people and reinvesting in our organization so that we can continue to best serve the interests of our members. In 2021, we welcomed the addition of five new employees to support the Pension Administration, Investment and Communications teams—adding critical bench strength to our organization.
Once again, I would like to acknowledge the hard work and dedication of our entire staff, who have worked tirelessly amid another challenging year to serve our members and move the organization forward. Among the many initiatives that we undertook in the past year, TTCPP staff continued work on developing our internal systems. This included upgrading the accounting book of record and implementing a new investment portfolio management system to provide meaningful portfolio risk insights to the Board. Paperless workflow processes were developed for managing pension payments and onboarding newly retired members. Additionally, new and stronger measurement tools were developed to inform and guide the organization on how we are serving our members.
Enhancing our member service functions was an important focus for our staff. These efforts were most notably encapsulated by the refresh of our logo and our mission to give greater clarity to our purpose. In December, TTCPP also launched our first publicly available website, which now serves as an important resource for our members to access all manner of information about the Plan. In response to the challenges posed by the COVID-19 pandemic, we also introduced online webinars where members can learn about the Plan and what it means to them. In total, 254 members attended webinars, which were very well received based on follow-up surveys.
Efforts were also made in the past year to raise the profile of TTCPP through a range of touchpoints, including TTC channels, industry organizations and regulatory authorities, a peer plan communications roundtable, and establishment of a social media presence on LinkedIn.
While 2021 presented us with tremendous uncertainty, our organization has emerged stronger for it. As we look to the future, I am optimistic about the direction we are headed in, and I am confident in our ability to continue supporting our members—throughout their entire lives and on their way to retirement.