Tipnis told PRWeek that she was close to accepting a senior analyst position.
'I have decided that consulting is not the right thing for me and there is no point in trying to waste any more of Cubitt's time,' said Tipnis.
Tipnis handed in her notice three weeks ago and will leave Cubitt within a month.
She was previously an analyst at Saracen Investment Management and joined Cubitt in April, filling the gap left by the departure of Stephen Scott (PRWeek, 6 April).
She has also worked as an institutional fund manager at F&C and Schroders.
Cubitt managing partner Simon Brocklebank-Fowler said the firm had not yet decided whether to appoint a replacement and that a new head of retail IR would be brought in according to the needs of the business.
In April, Cubitt hired former Edelman financial practice director Michael Henman (PRWeek, 23 April).