蔡源福资深大律师擅于处理商事诉讼、公司法及金融服务、以及税务与衡平法这三个领域的事务。蔡大律师亦经常在海外的法庭或审裁处提供有关香港法律的专家意见。
在近三十年中，蔡大律师主要参与了许多重要的商法和公司法案件，其中包括 ADS v Wheelock Marden & Others (2000) 3 HKCFAR 70 这一终审法院案件。这一案件的审讯为期十四个月，是香港最长的民事审讯之一。蔡大律师在各个领域都曾与许多英国御用大律师及香港资深大律师共事，并经常处理国际性案件。
蔡大律师于1988年加入德辅大律师事务所，是在本事务所执业时间最长的大律师之一。
德辅大律师事务所的蔡源福资深大律师善于处理许多领域的法律业务，这其中包括税法和股东争议。他被形容为一个「非常勤奋与优秀的大律师」。有人认为他可能是全港最注重细节的大律师。（《钱伯斯指南（商业争议解决）》2016）蔡源福资深大律师被评论者评价为「法律意见十分有效、深入以及合理。」他在公司、金融及商事领域都十分活跃。
《钱伯斯指南（亚太）》（2009-2017）及《钱伯斯（全球）》（2018）
德辅大律师事务所的蔡源福资深大律师善于处理许多领域的法律业务，这其中包括税法和股东争议。他被形容为一个‘非常勤奋与优秀的大律师’。有人认为他可能是全港最注重细节的大律师。
《钱伯斯指南（商业争议解决）》2016
蔡源福资深大律师被评论者认为是「股东争议及相关诉讼的不错人选」，并且经常参与税法领域的案件。其他法律业者认为他「想问题非常周到，并且易于合作，十分友好」。
《钱伯斯指南（亚太）》(2009-2015)以及 《钱伯斯指南（国际）》(2015)
- 高等法院原讼法庭暂委法官（2008年12月起不时接受任命）
- 大律师公会纪律审裁处主席
- 上诉委员会（城市规划）主席
- 电讯（竞争条文）上诉委员会成员
- 较高级法院出庭发言权评核委员会成员
- 执法伤亡赔偿组委员会成员
- 香港大律师公会执行委员会成员（1999-2002年）
- 税务上诉委员会成员（1998-2002年）
Commercial and company litigation
- ADS v. Wheelock Marden & Others (2000) 3 HKCFAR 70, [2001] 2 BCLC 324. The leading Hong Kong authority on fraudulent trading under s.275 Companies Ordinance, and on misrepresentation. Appeared with David Oliver Q.C., following the C.A.’s decision ([1998] 3 HKC 153) where he appeared with Robert Ribeiro S.C. (as he then was). And was junior to Robert G. Kotewall, SC during the trial which lasted some 14 months.
- Re Wong To Yick Wood Lock Ointment Ltd [2003] 1 HKC 484 (C.A.). A leading Hong Kong authority in shareholders’ disputes seeking winding-up and alternative remedies for unfairly prejudicial conduct; and for striking out a winding up prayer.
- Manufacturers Life Insurance of Canada v. Harvest Hero International Ltd & Others [2002] 1 HKLRD 828 (C.A.). A leading case on Norwich Pharmacal relief in Hong Kong.
- Re Asia Television Limited [2015] 1 HKLRD 607. Appeared for minority shareholder in well publicised unfair prejudice petition under s.168A Companies Ordinance concerning proper corporate practice and requirements of free television station licence. Obtained exceptional relief whereby majority shareholders were ordered to sell their majority stake.
- Shih Hua Investment Co Ltd v. Zhong Aidong [2017] 3 HKC 393 Appeared for 50% shareholder on petition on unfair prejudice and just and equitable winding up. Obtained exceptional interim relief, to reconstitute board of directors with independent professionals.
Tax and Chancery litigation
- C.I.R. v. Kwong Mile Services Ltd (2004) 7 HKCFAR 275, [2004] 3 HKLRD 168 (C.F.A.). A leading authority on source of profits under s.14 Inland Revenue Ordinance. Appeared with Robert Kotewall S.C.
- Arrowtown Assets Ltd v. Collector of Stamp Revenue (2003) 3 HKCFAR 517, [2004] 1 HKLRD 77 (C.F.A.). The leading Hong Kong decision on the Ramsay doctrine of fiscal nullity, and for stamp duty relief for inter-group transfers under s.45 Stamp Duty Ordinance. Appeared with David Goldberg Q.C.
- C.I.R. v. Datatronic [2009] 4 HKLRD 675 (C.A.). A leading case involving manufacturing profits under s.14 Inland Revenue Ordinance.
- Re Estate of Au Kong Tim (No. 3) [2017] 4 HKLRD 284. Appeared in probate trial which took over 3 weeks, to successfully propound will of testator aged 92, with a large estate. Established due execution by assisted or guided hand, testamentary capacity, knowledge and approval.