Roughly 9,000 rowers will pour into Cambridge this weekend to compete in the 49th annual Head of the Charles Regatta. But the athletes will be far from the only visitors along the Charles this weekend, as upwards of 400,000 spectators are expected to be in attendance during the two-day event.

With so many individuals flocking to the river, the Regatta will require 1,400 volunteers alone, and the event has developed into an economic coup for the city of Cambridge.

According to statistics on the Head of the Charles website, the regatta weekend generates $4.8 million in local and state tax revenue. But the city is not the only local entity benefiting from the massive event.

The regatta weekend also provides a huge boost to local businesses and hotels in the area, generating around $47 million and making the weekend a key factor in the bottom lines of many Cambridge businesses.

Local business is far from the only entity to thrive on the money that is generated from the Head of the Charles, as the two-day event now features dozens of sponsors, such as New Balance and Sierra Nevada.

This year’s Regatta features four premier sponsors in BNY Mellon, Greater Boston Mini Cooper, Brooks Brothers, and the EMC Corporation.

“[Selecting sponsors] really works both ways,” said Fred Schoch, the executive director of the Head of the Charles Regatta. “It took me 20 years to get New Balance to say ‘yes,’ and we’re excited they did this year. They have been a fantastic partner, and I think they will be thrilled this year after they experience the event. Sometimes it’s serendipity and sometimes just persistence.”

Though the Head of the Charles is now a sponsor-laden event, the regatta has not always featured such an array of participating companies.

Until 1990, the Regatta relied heavily on the budget of the Metropolitan District Commission (MDC) for success. While the MDC still plays a role in organization, security, and cleanup for the Head of the Charles, that role was greatly lessened when BayBank signed on as the first corporate sponsor of the event 23 years ago.

BayBank remained the event’s major sponsor until 1997, along the way creating the first Head of the Charles website to report results. For a two-year period after 1997, the Regatta was once again without a major sponsor. But in 2000, Charles Schwab stepped in as a corporate sponsor, and the regatta has featured one or more such sponsors every year since.

For many companies, the advantages of signing on as a sponsor for Head of the Charles are clear. The Regatta attracts thousands of competitors and alumni from some of the world’s most prestigious universities to go along with the large contingent of local Cambridge and Boston spectators. This uniqueness is what made BNY Mellon, a financial management company, choose to become involved with the event.

“The sport of rowing offers a powerful metaphor for BNY Mellon’s emphasis on teamwork and collaboration,” wrote Larry Hughes, CEO of BNY Mellon, in an emailed statement. “It’s about working in unison.”

The company is also involved with other regattas, but to BNY Mellon, the Head of the Charles is special because of its annual success and Boston connection.

“Last year’s HOCR was a big success, drawing about 400,000 spectators.” Hughes wrote. “Given the importance of the HOCR as a premier international rowing event and its place as a Boston institution, we felt it was a great fit for a long-term relationship.”

Although the Head of the Charles benefits from major sponsorship such as BNY Mellon, Brooks Brothers, Sperry’s, and New Balance, smaller companies also use the event as a way to present themselves to the public. One example this year is the Boston Burger Company.