Pension transfer values dropped to their lowest level in the more than 12 months during September before rising again at the end of the month.
At one point during September the XPS Pensions Group Transfer Value Index dropped to £227,000.
But at the end of the month pension values stood at £230,000, compared to £232,000 at the end of August, and have been falling for several weeks.
Despite this, transfer values have been relatively stable for the past year.
In fact the index showed transfer values at the end of September were at the same level as they were in the same month last year and fluctuated by £9,000 during the intervening 12 months.
Sankar Mahalingham, head of defined benefit growth at XPS Pensions Group, said: "We have now seen a 12 month period of relatively stable transfer values.
"The index at the end of September 2018 stands at the same value as it did at the end of September 2017, £230,000, and has fluctuated by only £9,900 during that time.
"As we approach the deadline for agreeing a deal for Britain leaving the European Union, speculation about the type of deal negotiated, or indeed the possibility of a no deal scenario may impact gilt yield and inflation expectations, thereby increasing the volatility in the index."
XPS Pensions Group’s Transfer Value Index tracks the transfer value that would be provided by an example DB scheme to a member aged 64 who is currently entitled to a pension of £10,000 each year starting at age 65.
Since the introduction of pension freedoms in 2015, the number of people transferring out of their defined benefit pensions has been soaring, as savers seek to take advantage of sky-high transfer values and to move their nest eggs into defined contribution schemes in order to access their cash.
According to the Office for National Statistics, funds transferred out of pension schemes almost tripled to a record £34.2bn in 2017.