I purchased units in an MLP in late 2018. Did not receive any distributions in 2018. Is it certain I don’t owe taxes or should I wait until March when the K1 comes out?
It might be hard if you're expecting a refund, but you should always wait. The IRS's computers are looking to match what the LP reported concerning your tax ID (SSN) with what you report came from the LP. There may be some non-taxable information that the LP reports to the IRS that is included on your K1. Could be something irrelevant to you. Always think in terms of computers. The IRS vs. Intuit (TurboTax)
Its called the "matching program". The IRS computers look to match what a "3rd party" (employer (w2), investment company (1099-Div, etc.) reports to them, with the tax id (SSN) of those affected. It's pretty much their number one way to verify what your "reporting" is correct.