Tullett Prebon boss Terry Smith and finance director Paul Mainwaring have increased their stakes in the interdealer broker following the breakdown of bid talks. Chief executive Smith invested more than £1.2m. He bought 400,000 shares at 300.5p each. That takes his stake to 4.48%. Mainwaring invested £293,000 in 97,656 shares, which were acquired at the same price as Smith's. Mainwaring owns 0.1% of Tullett. On 13 May Tullett Prebon said that bid talks had ended because the two sides could not agree on a price. Prior to this announcement the shares were trading at 362p. The share price has continued to fall since the announcement. The director share buying has sparked a small recovery. Revenues fell 12% to £312m in the four months to April 2010 because of the effects of currency and broker defections. Even at constant exchange rates there was a 3% fall in revenues. In March, Tullett won a claim against BGC Partners in the High Court, after it was found that BGC unlawfully poached Tullett's brokers in London. Top Director BuysTullett Prebon (TLPR) Director name: Mr Terry SmithAmount purchased: 400,000 @ 300.50p Value: £1,202,000Tullett Prebon (TLPR) Director name: Mr Paul MainwaringAmount purchased: 97,656 @ 300.50p Value: £293,456Thomas Cook Group (TCG) Director name: Mr Manny Fontela-NovoaAmount purchased: 100,077 @ 198.50p Value: £198,653Melrose Resources (MRS) Director name: Mr Robert F M AdairAmount purchased: 20,000 @ 258.86p Value: £51,772Thomas Cook Group (TCG) Director name: Mr Paul HollingworthAmount purchased: 20,015 @ 198.50p Value: £39,730Thomas Cook Group (TCG) Director name: Mr Sam WeihagenAmount purchased: 20,000 @ 198.50p Value: £39,700Melrose Resources (MRS) Director name: Mr David Howard ThomasAmount purchased: 7,961 @ 264.41p Value: £21,050Melrose Resources (MRS) Director name: Mr David Howard ThomasAmount purchased: 6,900 @ 264.12p Value: £18,224Renovo Group (RNVO) Director name: Mr David BlainAmount purchased: 40,000 @ 25.45p Value: £10,180