# Swap curve and short maturities

Consider USD Libor 3M swap curve. There are different maturities:

2d, 1m, 3m, 6m, 9m, 1y, 18m etc.

The values for 3m, 6m, 9m etc. time buckets are just swap rates for swaps with floating leg equal to 3m libor, settlements every 3 months and maturities 3m,6m, 9m etc.

I wonder how the values for 2d or 1m are being calculated if the maturity is shorter than the settlement periods?

Obviously, you won't have a one-month swap with a 3m index. The shorter maturities are usually constructed by liquid short-term instruments such as: deposits. If those instruments are not used, you'll need an extrapolation scheme. This could be anything, like assuming a flat rate or some kind of equations. You'll need to find more from the contract specification.