THE RBB FUND TRUST 485BPOS

Exhibit 99.(l)(26)

FORM OF PURCHASE AGREEMENT

The RBB Fund Trust (the “Trust”), a Delaware statutory trust, and Opal Capital LLC (“Opal”), intending to be legally bound, hereby agree with each other as follows:

1. The Trust hereby offers Opal and Opal hereby purchases one (1) share (the “Share”) of the Pathfinder Disciplined Midcap Equity ETF (the “Fund”) at price per Share equivalent to the net asset value per Share of the Fund as determined on [ ].

2. The Trust hereby acknowledges receipt from Opal of funds in the amount of $[ ] in full payment for the Share.

3. Opal represents and warrants to the Trust that the Share is being acquired for investment purposes and not with a view to the distribution thereof.

4. This Agreement may be executed in counterparts, and all such counterparts taken together shall be deemed to constitute one and the same instrument.

IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of [ ].