Tenet has published guidelines for advisers in the event the UK leaves the European Union without a deal in March.
In a guide titled 'Investment advice under Brexit uncertainty' Tenet stated the process of the UK leaving the European Union should "not really change anything" with regard to establishing client objectives and suitability assessments.
But it warned Brexit could alter a client’s attitude to risk and consequently lead to a more "cautious medium-term" investment approach.
At the same time Tenet stated clients who are prepared to invest for the longer term should not be concerned about short-term fluctuations in their investment values.
Where phasing is used for large new investments, Tenet stated, it should be done over a short-term timeframe, as part of an agreed automatic series of investments at defined intervals.
The company warned a phased investment approach outside of these parameters could create a "real risk" of missed market growth, with future investment being overlooked.
Tenet stated its guide was designed to help advisers work with clients' investments in no-deal circumstances, highlighting the continuing importance of "objectives and suitability".
It stated it had published the guide against a backdrop of "significant uncertainty" in the UK’s economy as a result of the prospect of a no-deal Brexit.
Prime Minister Theresa May is in the process of trying to reach an agreement with the EU after her initial Brexit deal was voted down by MPs in January.
The deal proved controversial and several members of the Conservative Party called for Mrs May to stand down as Prime Minister, with some claiming it gave the EU too much power over the UK and others saying the opposite.
The financial adviser trade body Pimfa had backed the deal, after it had previously stressed the importance of prioritising the interests of retail clients during Brexit negotiations.
Meanwhile, earlier this month Tenet confirmed it had appointed a successor to replace current chief executive Martin Greenwood, who is due to leave the role later this year.