We are not long off now the US Midterm elections in November when the expectation is that the Democrats will lose control of the House but possibly improve their position in the Senate. At the moment this is split 50:50 with the Vice President having the casting vote.
As I noted here last week Betfair has a very different way of defining this market than Smarkets and includes an option for it to come out at 50:50 once again. It also does not include in seat totals those Senators who are not Democrats but Caucus with the Democrats. The current odds on the Republicans with both betting exchanges is 43%
I have yet to bet and am annoyed with myself for not getting on the Dems when they were longer than evens.