Rafael Henrique | Lightrocket | Getty ImagesHubSpot shares rallied 9% on Tuesday after CNBC's David Faber reported that Alphabet is looking at an all-stock offer for the software company.Reports of a potential deal first surfaced in early April, when Reuters published a story saying Alphabet was talking to advisors about making an offer for HubSpot. Bloomberg followed with a story earlier this month, indicating that talks were progressing."There have been many reports about HubSpot being in conv...