I have been told that cell phone contracts are sometimes a way to improve one's credit score.
This makes sense to me as a phone contract involves a commitment to pay monies at a regular interval, much like a loan, which contracts including a phone at a discounted up front rate effectively are.
However it is unclear to me (even after some Googling) if this extends to SIM only contracts. There is still a financial commitment however no loan as such.
My my question is this, is there any potential positive effect to one's credit score to take out a SIM only phone contract in the United States?