Wiranto noted that in the wake of the last major terrorist attack in Jakarta -- the 2009 bombings of two luxury hotels -- the effects petered out quickly.
OCBC's figures include direct tourism revenue, without extrapolating secondary effects such as restaurants and retail figures.
The World Travel & Tourism Council estimates that travel and tourism contributed 3.2 percent of Indonesia's gross domestic product (GDP) in 2014, while the total contribution was around 9.3 percent of GDP.
But the attacks may complicate efforts to revive the country's flagging economy and Indonesia's President Joko Widodo's initiative to drive tourism growth. ANZ estimated the attack could shave 0.25 percentage point off Indonesia's economic growth forecast for the first quarter.
"Foreign tourist arrivals had grown by 7.19 percent last year and this pace of growth could be expected to slow in 2016 given today's events," ANZ said in a note on Thursday.
But general ignorance may help keep the tourists coming. A 2013 poll from Australian opinion polling company Newspoll found that around 29 percent of all Australians claim to have visited Indonesia at some point, but only 70 percent knew that popular tourist destination Bali was in Indonesia. In 2013, around 11 percent of foreign tourist arrivals were from Australian residents.
There is, however, another potential reason markets kept their cool: The attacks, for which ISIS claimed responsibility, don't appear to have been carried out by the A-team, with some analysts calling them "amateurish." While apparently timed to coincide with a busy lunch period in a major shopping area, most of the casualties were the attackers themselves.
An Indonesian and a Canadian were killed in the attack and 20 people were wounded, Reuters reported. Five suicide bombers blew themselves up.
That may be because Indonesia's counter-terrorism forces had already moved in response to warnings late last year.
"They actually did a good job of cracking down in December against ISIS ringleaders and crews that were reported to be plotting widespread attacks geared toward Christmas and New Year's," noted Jonah Blank, senior political scientist at researcher Rand, on CNBC's The Rundown. "It's quite possible that the Indonesian (counterterrorism force) Detachment 88 and other units headed off a much, much bigger and more important attack and this is merely the residue."
Outside the financial markets, foreign investment into Indonesia will likely be closely watched, but it may not be affected much.
Lin Neumann, managing director of AmCham Indonesia, told CNBC's SquawkBox that terrorist attacks in the country aren't new and foreign companies operating in Indonesia already factorthe country's security situation into their decisions.
He found the effective police response to Thursday's attack encouraging.
"This is an overwhelmingly moderate progressive Muslim majority country and there is no tolerance here for this kind of activity," Neumann said. "The worst thing that could happen would be for people to conclude that it's a dangerous place for investment. I don't think it is and I think there hasn't been enough of this kind of activity to scare away investors."
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1