My medicaid eligibility ended 4/1/15 w/only 4 days notice due to making 257 more a month above poverty limit. If I sign up now through the marketplace when would my coverage begin based on this? Thank you in advance.
You qualify for special enrollment on the day you lose coverage. The new coverage can start as early as the day you lose coverage, but you can apply early.
To make this happen you'll typically have to enroll before you lose the old coverage. The rule of thumb with health insurance is that if you buy coverage before the 15th it starts on the 1st of the following month, if you enroll after the 15th it starts on the 1st of the next. So it's generally a wise move to enroll in special enrollment coverage 30 days before your special enrollment period starts.
Because you didn't get a solid 30 days to enroll before you lose coverage you have a few options. A) Simply enroll ASAP and see how early you can get coverage to start and B) appeal to Medicaid via your state Medicaid department and let them know the situation they put you in. You may be able to get some leeway.
The above is all rule of thumb, you'll always want to double check exact start and end dates. Also you'll need to make the first months payment before your coverage starts. It's also worth noting that Medicaid is unique as it can start up to two months retroactively (if a person would have qualified for coverage in those months but didn't enroll). So if you switch back to Medicaid keep this in mind, it can help avoid gaps in coverage.