How profitable is the movie production business? Owners of the major studios make it hard to tell; they typically blend movie and TV results in their financial reports. But MoffettNathanson Research’s Robert Fishman tries in a report this morning to unscramble the egg for Warner Bros, Fox, Disney and Paramount. And he likes what he sees as the studios control expenses and concentrate on tentpole movies.

The four studios generated $3.5 billion in cash flow from movies last year, the analyst estimates. (To be precise, he’s looking at EBITDA — the industry term for earnings with interest, taxes, depreciation and amortization added back in to minimize the impact of financing and accounting decisions.) That’s up 35% over 2013 and far exceeds every year going back to at least 2007. It also gave them a more-than-respectable profit margin of 14.4%.

Fishman figures the four studios generated $24.1 billion in film-related revenue, up 7.6% from 2013. That $1.7 billion increase was offset by just a $750 million increase in expenses, to $20.6 billion. Even with the increase, outlays were $1.7 billion lower than in  2011.

Fishman says the improvements show that “bigger-budget movies are more profitable than the midsize-budget movies that were cut back,” especially as more business comes from overseas.

But the good times might not last. “Risk factors include declining domestic attendance, an increasing number of film releases, new softness in home video and the negative impact of currency on reported international growth,” the analyst says.

That could have a ripple effect on exhibition chains. To compensate for weakening home video sales, studios might “get more aggressive with windowing” — offering new releases directly to consumers and undercutting theaters’ claim to be the exclusive venues for the latest hits.