If you got a 1099-B for this transfer, then this was a taxable event.
It all depends on how your broker handled this exchange. If he sold all the stocks that were in the investment account before he transferred them to your IRA, then you will have capital gains tax on the proceeds of the sale.
If he simply transferred your holdings from your investment account into your IRA, then there would be no tax on the portion that represents the basis.
And here is the problem for the broker. You paid tax on the basis of your account, but you won't pay tax on the earnings and the unrealized gain until you report the income on your tax return. To simply transfer a portion of the account means that some of the money is pre-tax, and some is after-tax, and he knows you want to take a deduction for the full amount transferred. He solved the problem by cashing out your holdings, so everything becomes after-tax, and now you qualify for that tax deduction when you move it into your IRA.
