The three-time Wimbledon champion Boris Becker has been found guilty at Southwark crown court in London of four charges under the Insolvency Act and acquitted of a further 20 counts relating to his 2017 bankruptcy.

The six-time grand slam winner, 54, was accused of hiding millions of pounds worth of assets, including two Wimbledon trophies, to avoid paying his debts.

The former men’s world No 1 tennis player was declared bankrupt on 21 June 2017 over an unpaid loan of almost £4m on his estate in Mallorca, Spain, in 2013, and £1.2m, with a 25% interest rate, borrowed from the British businessman John Caudwell the following year.

The court heard Becker, who has a previous conviction for tax evasion and attempted tax evasion in Germany in 2002, earned a “vast amount” of money, winning about $50m (about £38m) in prize money and sponsorship deals.

But Becker, who went on to coach current tennis star Novak Djokovic, said his earnings “reduced dramatically” following his retirement in 1999. The German national, who has lived in the UK since 2012, claimed he had cooperated with trustees tasked with securing his assets – even offering up his wedding ring – and had acted on expert advice.

In his closing speech, his defence barrister, Jonathan Laidlaw QC, had told jurors that Becker, who won 49 singles titles in 77 finals over 16 years, had relied heavily on advisers after he became famous and wealthy following his sporting successes.

He had been, said Laidlaw, “too trusting and reliant” on the advice given to him by the “numerous advisers” that surrounded him. Laidlaw said that while there was an element of Becker “burying his head in the sand” when it came to matters of money and finance, at the time of the bankruptcy Becker’s life was managed “chaotically” by these advisers.

Denying the prosecution’s claim that Becker had given bankruptcy officials the “runaround”, he said: “Some of those advisers were offering genuine good advice intended to be in the defendant’s best interest – others, as may be the way of the world, may have simply wanted a slice of the pie his fame and fortune offered.”

Rebecca Chalkley, prosecuting had argued that Becker’s evidence was not credible and that he was seeking to “hide behind his advisers”. “The obligations and duties were with him,” she told jurors, adding that Becker not knowing the location of the trophies that “defined his career” was “simply not credible”.

Some of Becker’s trophies were auctioned off for £700,000 to pay his debts and he has made various appeals to try to locate them. But after numerous attempts to recover the missing trophies, including a BBC campaign, they are yet to be found.

The prizes include two of his three Wimbledon men’s singles trophies, his 1992 Olympic gold medal, Australian Open trophies from 1991 and 1996, the President’s Cup from 1985 and 1989, his 1989 Davis Cup trophy and a Davis Cup gold coin that he won in 1988.

Becker, who was supported throughout the trial by his partner, Lilian de Carvalho Monteiro, was found guilty of the four charges by a jury on Friday, including removal of property, two counts of failing to disclose estate and concealing debt.

He was bailed ahead of sentencing at the same court on 29 April and could face a jail sentence carrying a maximum term of seven years for each count.

Alex Jay, the head of insolvency and asset recovery at the litigation firm Stewarts, said: “Make no mistake, being found guilty in a criminal court of bankruptcy offences is quite rare. Most people, when bankrupted, cooperate with the bankruptcy process, at least to a degree that doesn’t result in criminal charges being brought and proved. The level of Mr Becker’s attempts to frustrate the process, and avoid repaying his creditors, must therefore have been quite exceptional.”