Data from the Financial Ombudsman Service has cast doubt on the case for a long stop on liability for advice as the Financial Conduct Authority gets ready to review this issue next year.
Figures from the Fos showed the number of complaints against financial advisers, and the proportion of complaints being upheld, has been going down over the past four years.
The number of complaints lodged 15 years or more after the advice was provided were also decreasing.
This is significant because the long-standing fight in the adviser community for a time limit on their liability for the advice they have given - the so-called long stop - is proposed at 15 years.
The FCA has said it will review the case for a long stop in 2019 as part of its wider review of how the Financial Advice Market Review has panned out.
As part of this revisiting of the long stop issue, the regulator has said it will take into account the risk to advisers of not having an end date for liability, based in part on the number of complaints lodged with the Fos for advice given 15 or more years ago.
A downward trend for older complaints could be interpreted by the FCA as meaning the overall risk to advisers of historic complaints is small, diminishing the need for a sector-wide long stop.
The number of complaints against advisers between July 2014 and June 2015 was 3,496, with 39 per cent of these being upheld.
This compares to just 1,359 complaints between July 2017 and the end of April 2018, with 33 per cent of these upheld.
Meanwhile there has been a similar fall in the number of complaints relating to advice from 15 years ago or more.
In 2014/15 there were 489 such complaints, of which 35 per cent were upheld, while so far in 2017/18 there have been only 235, of which 29 per cent were upheld - only 68 complaints.
In the Financial Advice Market Review, the FCA ruled out the introduction of a 15-year long stop limitation period on complaints to the Fos because very few complaints actually fell into this category and an even smaller number were upheld.
But the regulator said that as part of the review of the FAMR in 2019, the FCA and HM Treasury would consider "any ongoing trends and the impact of the [Fos's] complaints data relating to advice on long-term products".
Keith Richards, chief executive of the Personal Finance Society, said: "Whilst there is a compelling argument for the reintroduction of a long-stop, based on professional equality, most adviser models have evolved to a more engaged and ongoing professional financial planning service.
"Therefore, although it seems unfair in principle not to have a level playing field in line with other professions, the debate around its relevance has become less significant.
"Data from the Ombudsman and the fact that the selling of 25-year term investment products is no longer the norm, means that the FCA could be seen to be reducing consumer protection via the reintroduction of a long-stop.