Strategic Scientific Reserve is a top secret government agency that was founded by Howard Stark.
Howard Stark is known to have worked for the American government during World War II as part as the Manhattan Project as well as creating Captain America’s uniform and S.H.I.E.L.D. The Howling Commandos are said to have been under Captain America’s command, while Colonel Chester Phillips recruited and mentored Steve Rogers and was possibly his direct commanding officer.
To combat the new HYDRA, Howard Stark, Nick Fury, and perhaps Chester Philips and others as well reform their old department under the new name of the Strategic Homeland Intervention, Enforcement and Logistics Division, better known as S.H.I.E.L.D.
Now in real life, the Office of Strategic Services was set up during World War II to coordinate and conduct espionage operations behind enemy lines. Disbanded after the war, it was later reformed into the Central Intelligence Agency.