Read question 41 of IRS notice 2008-59.
If an account beneficiary establishes an HSA, and later establishes another HSA, any later HSA is deemed to be established when the first HSA was established if the account beneficiary has an HSA with a balance greater than zero at any time during the 18-month period ending on the date the later HSA is established.
Example 1. An account beneficiary established an HSA on March 1, 2007. On June 15, 2007, he withdrew all the funds from the HSA, resulting in a zero balance. On November 21, 2008, he established a second HSA. Because the second HSA was established within 18 months of June 15, 2007, the second HSA is deemed to be established on March 1, 2007.
