Online share dealing rates for the current TD Sipp cost between £5.95 and £12.50 depending on trades in the previous 90 days and this will remain the same for the new TDDI Sipp.
Investors moving to AJ Bell will pay between £4.95 and £9.95 depending on trades in the previous month.
Mr Kovach added: "We firmly believe that BW Sipp LLP, will provide an improved product for all our customers and we are proud to offer it.
"One advantage among many is a straightforward automated process for account opening, account funding and drawdown. We know how important retirement plans are to our customers, which is why together with BW Sipp LLP we are committed to a long-term partnership to provide customers with a secure and convenient Sipp service at a simple price."
He added that the charging for the new Sipp would change in the next few months to make sure they are "clear, simple and competitive".