New investor Akamai Technologies also participated in the round alongside existing backers Safeguard Scientifics, Catalyst Investors, and Observatory Capital.
The company also said that it has increased its debt facility to $105m, bringing the total to more than $175m.
MediaMath said the funds will be used to support its new international offices in the EMEA, APAC, and Latin American markets.
Spring Lake partner Dan MacKeigan said, “We have been looking to back a leader in the digital marketing space for quite some time.
“MediaMath’s leading industry position, buoyed by their remarkable triple-digit year-over-year growth and best-in-class marketing platform, presented us with an opportunity that we could not pass up.
“They clearly have a keen understanding of a marketer’s needs and a compelling long-term strategic vision.”
In April this year Spring Lake led a $13m Series C for cloud-based B2B marketing data management services company NetProspex.