Neither of them, in fact, make much sense to me.

If you want to be internally consistent, at least on the mechanics of it, the second example is more appropriate, mirroring as it does the multiple punctuations with the multiple statements: 'concluded'; 'asking'; [the actual ask, which requests further asks], suggesting a complexity of scope.

But the base ideas are at odds precisely because of that complexity of scope: One cannot really 'conclude' with an interrogative. An interrogative, by its very nature, asks for continuation. Continuation is in opposition to conclusion, which is not simply 'stopping' as you imply here, but more the finding of a stopping place by a synthesis of prior ideas presented in service to a stated precept or precepts. The questions that may be presented are, one hopes, in service to the conclusion, or the concluding. To make it more clear, you might qualify, a la, 'He concluded his formal remarks by asking...' but that still kinda confuses me.

Myself, I think I would make it almost all dialogue:

He asked, "Are there any questions before I conclude my remarks?"