May 21, 2015 · 4 minutes

Through a maze of hallways, each indistinguishable from the next, in the still very under-construction and hard to find HULT International School of Business on the Boston-Cambridge line, the world's largest startup accelerator, MassChallenge, held the official welcoming ceremony yesterday afternoon for the 128 startups that will be joining its four-month bootcamp for early stage companies.

It was an appropriate setting for the organization that may be Boston's greatest contribution to the U.S. startup ecosystem, and yet gets overlooked in the discussion of the East Coast's most innovative tech-focused organizations, among them Codecademy, Flatiron School, the Boston and New York Techstars, and Betaworks.

It's even overshadowed in the Boston-area by a handful of recognizable tech companies, including TripAdvisor, Kayak, Wayfair, Akamai, Care.com, DraftKings, and HubSpot. But MassChallenge, one of the city's non-profits, is on the cusp of becoming an internationally recognized brand with the chance to make an impact on a massive global scale.

While yesterday officially marked the start of this year's program in Boston, the accelerator also unveiled the 90 companies that will be participating in MassChallenge UK — the second global expansion for the accelerator, with Israel being the first. Next week, many of the same members of the MassChallenge team that welcomed the broad group of startups to its original program will be in London to do the same for its first European outpost.

But while it's impressive that the accelerator currently helps more than 200 early stage companies gain traction in the U.S. and abroad, it's the organization's next moves that may make it a literal 500 startups.

MassChallenge is unique among startup programs and competitions in that it doesn't take any equity in the companies that participate in its programs. For that reason, among others, MassChallenge has appealed to government programs in places like Russia, Brazil, Columbia, and many others that are trying to promote entrepreneurship in their home nations. MassChallenge has claimed to be the largest startup accelerator in the world just due to the number of companies that take part in its program each year; it may also be able to stake a claim to that title due to its massive global presence.

Just this week, in addition to selecting a couple hundred companies from the more than 2,000 that applied to the program, MassChallenge also revealed that Israel Ganot, the co-founder of device return company Gazelle, will be taking over leadership of MassChallenge Israel as its managing director.

A large number of MassChallenge's sponsors — which subsidize the program and its financial grants that range from $10,000 to $100,000 — are either multi-national corporations or the business development arms of nations in Europe, Asia, and South America. Chatting with John Harthorne, a co-founder and the chief executive of MassChallenge, the organization is being approached by so many countries and businesses looking to partner with the program, it is having to turn people away.

Harthorne himself is the central figure to MassChallenge's international growth, and yet he often stays in the wings and lets the young crop of MassChallenge's emerging leadership team be the public face of the program. I haven't seen his travel itinerary from the past year, but judging from what folks within the organization have said as well as his attendance at public events over the past years, it wouldn't be hard to estimate that Harthorne has spent at least half the year traveling to potential new MassChallenge sites abroad. Although nothing is official, MassChallenge already has official agreements to partner with the governments of Germany, Russia, France, and a host of others, in the near future. Rumors of MassChallenge programs in South America and Africa are as constant as Harthorne's trips to the international terminal at Logan Airport.

And while its growth is one of the main reasons to watch MassChallenge going forward, the role it plays in helping early stage companies, even beyond tech, is why it has such an appeal to entrepreneurs.

While companies coming out of the Techstars Boston program have often gained more public attention, quite a few got their start at MassChallenge, including fast-growing Localytics. But, because of the breadth of startups in its program, MassChallenge companies are making a bigger impact. Just take two companies that took part in the program two years ago. One, Silverside Detectors, created a sensor system, which can be setup at tollbooths around major metropolitan areas, that can detect if someone is trying to bring nuclear materials into a city. The other, the MIT-built UPower, created a nuclear reactor that can power a city, which is the size of a dorm room refrigerator.

The companies that were accepted into this year's MassChallenge program range from the usual group of payments and transportation tech companies, to outliers like Six Foods, which makes edible cricket chips, to Unshrinkit, a developer of a product that can fix clothes accidentally shrunken, to one company trying to develop a way to fuel cars while they are driving.

Talking to a few of the companies yesterday, there was a general excitement at having been accepted into the program. And, while its international growth is a metric to point to for the program's potential success, the full impact of MassChallenge won't be known for a number of years, quite possibly when the companies that have gone through the program start to become the massive multi-national corporations that subsidize the program.