It has a fully completed corrective ( A ) – ( B ) – ( C ) down structure off the top made at $43.50 made in February 2008.
On 2 hour chart we can see that DBA has to take over $17.00 to prove it has bottomed
DBA - weekly chart updated on 6/13/2019
Normally each reversal of a long-term down trend goes through that Inverse Head and Shoulders reversal structure which becomes a launchpad for a rally. I would be a buyer after a corrective looking pullback that should follow that rally.