Equipment and industrial analyst Stephen Tusa reiterated both his underweight rating and $10 price target for GE shares Monday, telling clients that investors may be wrong to celebrate the switch given the suspicious timing. Flannery took on the job in August 2017.
"A change of this magnitude at this point, with no real details and no conference call, is negative, in our view. It could be that there are preparations that need to be made in providing more details and holding a conference call but we think it brings into question how serious the situation is," Tusa wrote Monday.
GE shares closed up 7 percent Monday to $12.09.
General Electric's board of directors removed Flannery thanks to frustration with the pace of his turnaround plan for the embattled industrial conglomerate, sources familiar with the situation told CNBC.
Tusa's price target is the lowest on Wall Street and represents more than 11 percent downside from Friday's close at $11.29.
Culp's time at Danaher "could not have been more different to this with a very clean balance sheet, no dividend, and generally solid short cycle businesses," Tusa added.
"We fully expect him to do well, positive for long term investor confidence, but which we believe also means a proper reset to earnings and FCF construct and potential recapitalization to de-risk the balance sheet, all of which represent the most important 'shoes to drop,'" he said.