Mutual fund giant Vanguard on Friday opened a new office building in Malvern that bolsters its footprint in Philadelphia’s suburbs.

The 225,000-square-foot, four-story building named Neptune — a reference to the Royal Navy’s HMS Neptune, in keeping with the company’s convention of referencing nautical terminology and ships — will house 1,350 employees, who will begin moving in Monday, company management said.

The office, which took two years to build, is the first addition to Vanguard’s 87-acre Malvern West campus since it bought two buildings, now named Orion and Defence, from Pfizer in 2012. Pedestrian walkways connect Neptune, at 1300 Brennan Blvd., to Orion and Defence, at 100 Vanguard Blvd.

“Like any large construction project, it was not without its challenges,” Gordon Hurrell, Vanguard’s head of real estate and project management, said at a formal opening of the building Friday. “From weather to labor availability in this very hot construction market, to a few design tweaks" made at the last minute, it was one of the most “nail-biting finishes” he had seen.

Company officials did not say how much the project cost.

The majority of the employees at Neptune are part of the retail investor group, the company’s largest division that offers to clients funds, exchange-traded funds, brokerage services, and financial advice, said Melissa Kennedy, a spokesperson for Vanguard.

Contractors and consultants “from a variety of companies” also will be on site, said Paul Begin, the company’s head of global workplace experience.

Vanguard, which recorded more than $5 trillion in assets as of September and historically ranked among the biggest taxpayers to the Tredyffrin/Easttown School District, has long aimed to construct a new campus.

In 2002, the company bought Happy Days Farm in Uwchlan Township, a 200-acre property boxed in by highways. After doing little with the property for more than a decade, Vanguard recently listed it for sale in pursuit of “more favorable real estate purchases,” a spokesperson said over the summer. A 2018 assessment valued the property at around $960,000.

100 Vanguard Blvd., a 56-acre property owned by Horatio Realty Trust, was assessed in December at $35.8 million, according to Chester County property records. It is down from the late 1990s, when it was assessed at $65.6 million, and $47.15 million in 2012. No public tax records are yet listed for Neptune.