Fallon, Fergal Lynch and Darren Williams, plus trainer Karl Burke, were among 16 people detained in dawn raids following an operation co-ordinated by City Of London police.
Fallon was later released on bail from Bury St Edmunds police station and whisked away in a car. He will be required to attend a police station in London in two months' time.
In a statement, his solicitor Christopher Stewart-Moore said: "Kieren Fallon has not been charged with any offence. Following an interview with the police in Bury St Edmunds he has been released without charge.
"The circumstances that relate to his arrest involve an individual who Kieren Fallon has met on one occasion and whose name he did not even know at the time the meeting happened.
"This was during the course of a 10-minute car journey from Leicester races to the airport at Leicester, where he then flew on to an evening meeting at Windsor. During this car journey Kieren Fallon did not speak to the individual concerned. In the circumstances, we do not anticipate that this matter will be taken any further by the police."
Fallon, Lynch and Williams are expected to be back in action today - all three have booked rides, with Fallon due at Salisbury, Lynch at Redcar and Williams at Carlisle.
Jockey Club public relations director John Maxse said: "In the event that those concerned are released, then I would anticipate that they would be able to continue with their racing and riding, pending any further developments in the police investigation."
In response to the arrests, Andrew Chalk of Jockeys' Association solicitors Withy King said: "We have been familiarised with certain aspects of the investigation, but it would obviously be premature to discuss it at this stage.
"However, I would like to emphasise that the arrests do not mean anything in themselves. An arrest enables the police to search premises and seize documents, as part of the information-gathering process. It does not mean that the arrested person is guilty of anything."
Jockey's Association chief executive John Blake admitted that the very nature of racing means the sport will always attract unwanted publicity from time to time.
"Racing is inextricably linked to betting and there is an element of suspicion about almost every single day, in terms of punters who have bets on races which don't work out how their opinion thinks it would. They may be a bit suspicious of the jockey or trainer.
"The betting landscape has changed in the last few years in terms of betting exchanges and I think that is the important point to make. They give people the ability to back a horse to lose in a race and I think that has cast a lot of suspicion on the motives of individuals, whether they be trainers, owners or indeed jockeys."
"People have to make their own minds up about these things, but the headlines are not great for racing and we would be the first to admit that."
The growth of exchange has spawned firms such as Betfair and Betdaq, though traditional bookmakers have been increasingly attracted to the facility themselves in order to lay off bets and balance their books.
Punters also have the opportunity to bet 'in-running' - after a race has started. Some reports suggest Betfair alone attracts around £50m of business a week.
Former British Horseracing Board chairman Peter Savill has long been a fierce critic of the exchanges, though, and believes issues surrounding them are of "critical importance" to the industry.
He said recently that "nothing less than the future of one of Britain's most prestigious sports and industries and one of the greatest contributors to Government revenues is at stake".
Savill was concerned that punters using betting exchanges can make a profit out of horses losing, rather than just by backing them to win, and he saw this as a major threat to the integrity of the sport.
"Betting exchanges have, for the first time ever, suddenly and immediately enfranchised 30 million-plus people in Britain to make money out of horses losing races," he said.
"Previously there were only 3,791 people - the number of on- and off-course bookmakers with permits who had passed the 'fit and proper person' test - who were so enfranchised.
"But when you add to that 30 million figure every other person in the world with the desire to make money out of horses in Britain losing races - including, possibly, illegal Far East bookmakers and even organised crime - you have to wonder whether the decision was reached after appropriate research and analysis."
Betdaq spokesman Rob Hartnett defended the betting exchanges and highlighted their ability to provide a paper trail of the activities of members.
"The ability of an online company to monitor all the bets and attribute every single bet to every single account holder as they place a bet does actually enable the authorities to take a much more granular look at what has actually happened.
"If you walk into a betting shop and you place a bet and walk out, there's no record that you have placed that bet in any shape or form.
"With an online exchange, there is a record of every bet struck, and all the betting exchanges have worked with the Jockey Club and other sporting authorities to make sure that the sport is run properly and cleanly."
He added: "Hopefully, even though there may be some short-term pain after the arrests, in the longer term I think people's view is that the sport is clean and well-run and well-managed."
Date of birth: 22 February 1965
Place of birth: Clare.
Champion jockey: Six times (1997-1999, 2001-2003)
English Classic wins: 10 (All except St Leger)
2003 wins: 221
2002 wins: 149
2001 wins: 166
2000 wins: 59