"initial speculation" is a correct and usable phrase in written English.
You can use it to refer to tentative ideas or theories about a topic. For example: "The initial speculation was that the missing money had been stolen, but it was later discovered to be misfiled."
Although some of the five defendants arrested in Mr. Battaglia's death claimed to be part of the Latin Kings gang, the Nassau police said his killing was not related to a gang initiation, an initial speculation.
The team's initial speculation turned out to be close to what other experts had concluded.
The police firmly discounted initial speculation that the hall had been hit by a terrorist bombing.
Initial speculation had been that most of the pictures were "degenerate art" looted or confiscated by the Nazis.
There was initial speculation that the attack may have been the result of 'road rage' following a car crash.
There was initial speculation that McKiernan was taking the fall for a US air raid in Farah province last week in which more than 100 civilians were killed.
Initial speculations on an intermediate status of R. felis, with phenotypic properties similar to R. typhi but a genetic clustering with spotted fever group rickettsiae, resulted from studies that have not been reproduced [1], [8] [11], [25], [26].
First, initial speculations were provoked by the discovery of a family of enzymes with DNA deaminase activity and distinct local preferences [ 19, 29, 30].
The valuation at €550m is higher than initial press speculation in July ($500m) and... the sale would be accretive to the group's return on equity.
Initial industry speculation stated that DJ Tiësto would be involved with the game, but this was eventually denied.
There was initial fanfare and speculation as to the authenticity of its claims; Dunstan dismissed the book as a "farrago of lies" in his 1981 memoirs, entitled Felicia.
