The 770 open claims equate to £173m; last year there were only 323 open claims, worth £103m.
The value of claims against the fund now stands at £214m, an increase of 27% year-on-year.
However 280 of the mortgage claims are currently held in abeyance awaiting the outcome of potential insurance settlements.
The SRA has also revealed that it is attempting to find how many of the claims being made are actually from lenders who want to preserve their position.
So far this year there has been 42 claims worth £11m regarding unredeemed mortgages.
Legal futures revealed that the SRA typically ends up paying out significantly less than the total value of claims submitted.
Last year it closed claims totalling £87m but only paid out £22m, 26% of the total.
