The U.S. Patent and Trademark Office has released nine more blockchain-related patent applications filed by Bank of America.

Data collected shows that the applications – which relate to conducting and settling transactions within a payment network – were all filed February 22. To date, Bank of America has filed more than 30 known patent applications related to the technology, including as many as 18 during 2016 alone.

Combined, the breadth of the applications suggests that work is being done on blockchain-based payment systems within Bank of America. At the same time, the bank has issued no definitive statements on the subject to date, and it's not clear whether any of the proposed inventions will see the light of day.