Sony still owns him, Marvel brought him on lease while they were prepping to launch a shared universe with Spider and Robbie Reyes/ Ghost Rider in it. With the latter being a big shot of Shield.
There lies his crown in water deep, till Durin wakes again from sleep.

No, the deal is such that Sony pays for the full budget of the Spider-man solo movies and nets all the profits while Marvel likewise pays for the full budget of all their MCU films and nets all of the profits, even if spider-man appears in one of them.
This was reported on awhile back. Quick example of a source that easily came up when doing a search:
Sony Pictures will continue to finance, distribute, own and have final creative control of the Spider-Man films.
Source:
http://www.cinemablend.com/new/Spider-Man-Start-Appearing-Marvel-Movies-Landmark-Deal-69685.html
Regarding the creative control bit; Marvel has been making the creative decisions, but they need final approval from Sony who Marvel has said has been being amenable to most of what they want. Sony studio execs also viewed Civil War and provided Marvel with notes regarding the Spider-man bits as they have final creative control over how he is depicted in those films as well.
It's basically like a director-studio situation. There are times when a studio will defer to a director's creative impulses and let them do most to all of what they want. This is one of those times. The only thing, though, is that such an arrangement could change at any time, leading to a studio to make as many or as few creative demands as they want as they have final say. That's also the case here.

HMM Maybe, I just read that they initially dissagreed on who to cast as Spidey cuz Sony was paying for everything.
Lose the Game!!!!!!!

Do you think it might've been co-financed by Sony and Marvel? That was my initial impression

Marvels making it but Sony distributes and I believe they funded it as well.
Lose the Game!!!!!!!

I'm under the impression that it's a MARVEL film being distributed by SONY, correct?
correct.
Spider-Man: Homecoming
Directed by
Jon Watts
Produced by
Kevin Feige
Amy Pascal
Screenplay by
Jonathan M. Goldstein
John Francis Daley
Jon Watts
Christopher Ford
Chris McKenna
Erik Sommers
Based on Spider-Man
by Stan Lee
Steve Ditko
Starring
Tom Holland
Michael Keaton
Zendaya
Donald Glover
Jacob Batalon
Laura Harrier
Tony Revolori
Tyne Daly
Bokeem Woodbine
Marisa Tomei
Robert Downey Jr.
Music by
Michael Giacchino
Production company
Marvel Studios
Columbia Pictures
LStar Capital
Distributed by
Sony Pictures