When Defense Secretary Chuck Hagel was discussing possible effects of sequestration he only briefly mentioned the Marine Corps. The outlook was quite bleak, however, with the Corps size to be reduced to as few as 150,000 Marines.
The Marine Corps is already planning to reduce their number to 182,100 Marines by the end of 2016, with the Marine Corps Commandant Gen. Jim Amos mentioning the possibility of cutting up to 8,000 additional Marines on top of that due to sequestration, bringing the Corps down to 174,000.
During the height of the wars in Iraq and Afghanistan, the Marine Corps had around 202,000, and is shrinking by 5,000 Marines each year, in order to reach its goal of 182,100 Marines by 2016. The cuts to reduce the Corps down to 150,000 would require a further 18% cut in personnel.
When discussing reducing the Corps to 174,000 from the planned 182,100 Marines, Gen. Amos said that those cuts would have consequences for the readiness and capabilities of the Marines, as well as requiring the Marine Corps to potentially break contracts with some enlisted Marines. It's unclear what would be the consequences of reducing the Corps from 174,000 to 150,000 Marines.